<PAGE>

--------------------------------------------------------------------------------
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                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                               ----------------

                                   Form 10-K

[X]Annual Report Pursuant to Section 13 or 15(d) of the Securities Exchange Act
   of 1934 for the Fiscal Year Ended December 31, 1999
                                       or

[_]Transition Report Pursuant to Section 13 or 15(d) of the Securities Exchange
   Act of 1934

   for the transition period from              to

                         Commission File Number 0-25996

                               ----------------

                             TRANSWITCH CORPORATION
             (Exact name of Registrant as Specified in its Charter)

                Delaware                               06-1236189
        (State of Incorporation)        (I.R.S. Employer Identification Number)

                             Three Enterprise Drive
                           Shelton, Connecticut 06484
                    (Address of Principal Executive Offices)

                            Telephone (203) 929-8810

                               ----------------

   Indicate by check mark whether the registrant (1) has filed all reports
required to be filed by Section 13 or 15(d) of the Securities Exchange Act of
1934 during the preceding 12 months (or for such shorter period that the
registrant was required to file such reports), and (2) has been subject to such
filing requirements for the past 90 days. Yes [X] No [_]

   Indicate by check mark if disclosure of delinquent filers pursuant to Item
405 of Regulation S-K is not contained herein, and will not be contained, to
the best of Registrant's knowledge, in definitive proxy or information
statements incorporated by reference in Part III of this Form 10-K or any
amendment to this Form 10-K. [_]

   The aggregate market value of the voting stock held by non-affiliates of the
Registrant, based upon the closing sale price of Common Stock on February 29,
2000, as reported on the Nasdaq National Market, was approximately
$4,040,739,460. Shares of Common Stock held by each executive officer and
director and by each person who to the Company's knowledge owns 5% or more of
the outstanding voting stock have been excluded in that such persons may be
deemed to be affiliates. This determination of affiliate status is not
necessarily a conclusive determination for other purposes.

Common Stock, par value $.001 per share, outstanding at February 29, 2000:
39,947,163

                      DOCUMENTS INCORPORATED BY REFERENCE

   Parts of the following document are incorporated by reference in Part III of
this Form 10-K Report:
Proxy Statement for Registrant's 2000 Annual Meeting of Shareholders--Items 10,
11, 12 and 13.

--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
<PAGE>

                                     PART I

ITEM 1. BUSINESS

   The following description of the Company's business should be read in
conjunction with the information included elsewhere in this document. The
description contains certain forward-looking statements that involve risks and
uncertainties. When used in this document, the words "intend," "believe,"
"estimate," "plan" and "expect" and similar expressions as they relate to the
Company are included to identify forward-looking statements. TranSwitch
Corporation's actual results could differ materially from the results discussed
in the forward-looking statements as a result of certain of the risk factors
set forth elsewhere in this document. See also, "Item 7. Management's
Discussion and Analysis of Financial Condition and Results of Operations-
Certain Factors That May Affect Future Results."

General

   TranSwitch Corporation, a Delaware corporation established in April 1988
("TranSwitch" or the "Company"), designs, develops, markets and supports highly
integrated digital and mixed-signal (analog and digital) semiconductor
solutions for the telecommunications and data communications markets. The
Company's customers are original equipment manufacturers (OEMs) who serve three
communications market segments: the worldwide public network infrastructure
that supports voice and data communications, internet infrastructure and
corporate wide area networks (WANs).

   The Company's products are Very Large Scale Integrated (VLSI) semiconductor
devices that provide core functionality for communications network equipment.
The Company's VLSI solutions are programmable to provide high levels of
functionality for high-speed broadband communication networks. These products
are incorporated into OEM's networking equipment. TranSwitch's VLSI devices are
compliant with SONET/SDH (Synchronous Optical Network/Synchronous Digital
Hierarchy), asynchronous and ATM (Asynchronous Transfer Mode) standards. The
Company's mixed-signal and digital design capability, together with its
telecommunications systems expertise, enables it to determine and implement
optimal combinations of design elements for enhanced functionality. The Company
believes that this approach allows its customers to achieve faster time to
market and to introduce systems that offer greater functionality, improved
performance, lower power dissipation, reduced system size and cost and greater
reliability relative to discreet solutions.

Products and Applications

   TranSwitch supplies high-speed broadband VLSI semiconductor devices to
systems vendors who serve three fast-growing market segments: the worldwide
public network infrastructure that supports both voice and data communications,
the Internet infrastructure that supports the World Wide Web and other data
services and corporate WANs. The Company's core competencies as a systems-on-
chip innovation leader include:

  -- an in-depth understanding of SONET/SDH, asynchronous and ATM standards;

  -- the ability to design complex mixed-signal high-speed VLSI devices; and

  -- the capability to verify the design against customers' requirements and
     industry standards through analysis, simulation and certification.

   The Company's three product lines consist of SONET/SDH, asynchronous and ATM
products. The Company believes that its chip-set approach and broad product
coverage in all three product lines position it as a "one stop source" for
broadband communications VLSI products. Network equipment vendors can mix and
match TranSwitch's VLSI devices to optimally configure a specific system. The
Company's product lines can be combined to provide a cost-effective solution
with increased functional integration and features, while providing seamless
integration of SONET/SDH, asynchronous and ATM/Internet protocol applications.

   The prices for the Company's products typically range from approximately $20
to $300, depending on volume, complexity and functionality.

                                       1
<PAGE>

 SONET/SDH Products

   In the SONET/SDH area, the Company offers devices that provide a direct
interface for fiber optic transmission in North America, Europe and the Far
East. The Company's mappers, which bridge the interconnection between SONET/SDH
equipment and asynchronous equipment, allow DS-series and E-series transmission
lines to be connected with SONET/SDH lines. In this way, these mappers
transparently transport asynchronous signals across the SONET/SDH network.

   TranSwitch's current SONET/SDH products are used to build add/drop
multiplexers, digital cross connects and other telecommunications and data
communications equipment. This equipment is configured for use in both domestic
and international fiber-based public networks. The Company's SONET/SDH products
also have applications in customer premise equipment products such as routers
and hubs in central offices, adding integrated fiber optic transmission
capability to telephone switches.

 Asynchronous Products

   TranSwitch's asynchronous products provide high bandwidth connections and
can be used to configure transmission products for use in the public network.
This equipment is used to increase the capacity of the copper-based public
network. TranSwitch's asynchronous VLSI solutions also include customer
premises equipment products such as hubs and routers used in WANs and LANs to
access the public network for voice and data communication with similar
products in other locations.

   TranSwitch's asynchronous products provide high levels of integration, as
well as cost, power and performance advantages relative to discrete and
competing integrated circuit solutions. The Company's asynchronous VLSI
products include devices that provide solutions for DS-1 through DS-3 and E-1
through E-3 transmission lines. This product line also includes multiplexers,
which are devices that combine multiple low-speed lines to form a higher speed
line, and demultiplexers, which perform the reverse function. In addition, the
Company offers framers, devices that identify the starting point of defined bit
streams and enable systems to recognize the remaining bits.

 ATM Products

   TranSwitch's ATM family of products target the core elements of ATM-based
multi-service access multiplexer systems. The Company's ATM products also
include VLSI semiconductor devices for line interfacing and service adapter
functions. TranSwitch's CellBus is a system architecture for implementing ATM
access multiplexers and ATM switching systems.

Technology

   The Company believes that one of its core competencies is the
telecommunications and data communications knowledge and expertise of its key
executives and its systems engineering organization. The systems engineering
group possesses substantial telecommunications and data communications design
experience, as well as extensive knowledge of relevant standards. This includes
not only a thorough understanding of the actual written standards, but also an
awareness of and appreciation for the nuances associated with these standards
necessary for assuring that device designs are fully compliant. The Company
believes that its telecommunications and data communications experience and its
participation in the standards development process provide it with significant
advantages in designing semiconductor devices meeting the evolving needs of its
customers.

   Complementing the Company's accumulated communications industry expertise is
its VLSI design competence. The Company's VLSI design staff has extensive
experience in designing analog and mixed-signal devices, which require a
sophisticated understanding of complex technology, as well as the specifics of
manufacturing processes and their resulting impact on device performance.
TranSwitch has also developed a

                                       2
<PAGE>

large number of VLSI blocks that operate under the demanding requirements of
the telecommunications and data communications industry. These blocks have been
designed using standard VLSI-oriented programming languages such as VHDL and M
(a C-like language) to create new devices that meet expanding customer
requirements. Availability of these blocks and ability to access higher density
manufacturing processes allow the Company to develop a device to execute
multiple functions that were previously available only from a combination of
discrete devices.

   TranSwitch has also developed proprietary toolsets called "Test Benches,"
which facilitate on-time development of products and help assure that products
meet customer and standards requirements. These Test Benches consist of
behavior models of all applicable functions in a high level design environment.
These Test Benches also include test signal generators and analyzers such as
models of SONET/SDH signals. Systems engineers use Test Benches to test new
architectural concepts, while VLSI designers use Test Benches to ensure that
the device conforms to product specifications. The Company believes that the
availability of Test Benches provides it with a competitive advantage.

   The Company has invested significant resources in developing an architecture
that allows increased programmability. Programmability provides accelerated
time-to-market by decoupling hardware and software verification. In addition,
programmability permits standards upgrades and fixes to be effected more
easily. Further, customers can have the flexibility to tailor their products to
their specific requirements.

   The Company has also developed expertise and hardware/software tools to
certify products against customer and standards requirements. While the Test
Bench is used to test the software model of the VLSI device, these
certification tools are used to verify operation of actual device prototypes.
The Company shares its certification board, the platform used to certify a
particular device, with sponsoring customers, thereby accelerating their time
to market. The Company's certification approach and tools have been recognized
by customers as a key benefit.

Sales and Marketing

   TranSwitch's marketing strategy focuses on key customer sponsorships to
promote early adoption of the Company's VLSI devices in the products of system
vendors who are market leaders. Through the Company's customer sponsorship
program, customers provide direct feedback on product specifications and
applications while participating in product testing in parallel with the
Company's certification process. This approach accelerates customers' time to
market while enabling the Company to achieve early design wins for its products
and derive non-recurring engineering expense support and volume commitments for
specific products from these sponsors.

   TranSwitch's sales strategy is to focus on worldwide suppliers of high-speed
communications and communications-oriented equipment. These customers are
easily identifiable and include telecommunications, data communications,
internet, customer premise equipment, computing, process control and defense
equipment vendors. The Company has established a direct sales force and a
worldwide network of independent distributors and sales representatives for
marketing its products.

   TranSwitch's direct sales force, technical support personnel and key
engineers work together in teams to support key customers. TranSwitch has
located technical support capabilities in key geographical locations, including
Europe and the Far East. These field sales engineers and independent
distributors and sales representatives support the Company's customers.
TranSwitch maintains a technical support team at the Company's headquarters as
a backup to the field sales engineers.

   TranSwitch has established foreign distributors and sales representative
relationships in Australia, Benelux, Canada, China, France, Germany, Great
Britain, Israel, Italy, Japan, Korea, Spain, Sweden, Switzerland and Taiwan.
The Company also sells its products through domestic distributors and a network
of domestic sales representatives. The Company has regional sales and technical
support capabilities in Boston, Ma., Chicago,

                                       3
<PAGE>

Ill., San Jose, Ca., Morristown, N.J., Atlanta Ga., Ottawa, Ontario, Canada,
Brussels, Belgium, and Taipei, Taiwan, as well as in its headquarters facility
in Shelton, Connecticut.

Customers

   Since shipping its first product in 1990, the Company has sold its products
and services to over 400 customers. The Company's customers include: public
network systems suppliers that incorporate the Company's products into
telecommunications systems; WAN and LAN equipment suppliers; Internet oriented
OEMs; communications test and performance measurement equipment suppliers; and
government, university and private laboratories that use the Company's products
in advanced public network; and WAN/LAN development projects.

   Foreign sales all of which are denominated in US dollars, represented 30%,
46% and 33% of total revenues during 1999, 1998 and 1997, respectively.

   The following revenues from customers is based on the geographic location of
the Company's customers. All sales to foreign customers are exported from the
United States and are denominated in U.S. dollars.

<TABLE>
<CAPTION>
                                              Year ended December 31,
                                      ----------------------------------------
                Country                   1999          1998          1997
                -------               ------------- ------------  ------------
                                      (in millions) (in millions) (in millions)
   <S>                                <C>           <C>           <C>
   United States.....................     $49.8        $23.7         $18.1
   Israel............................       2.9          5.8            .5
   China.............................       2.4          7.2           1.8
   Other countries...................      16.3          7.5           6.7
                                          -----        -----         -----
     Total revenues..................     $71.4        $44.2         $27.1

   The following table sets forth for the periods indicated, the percentage of
the Company's total revenues derived from its significant distributors and
customers listed below:

<CAPTION>
                                              Year ended December 31,
                                      ----------------------------------------
              Distributors                1999          1998          1997
              ------------            ------------- ------------  ------------
   <S>                                <C>           <C>           <C>
   Insight Electronics, Inc. (1).....        34%          20%           41%
   Arrow Electronics, Inc. (2).......        19%          17%            *
   Columbia Technology (1)...........         *           15%            *
<CAPTION>
               Customers                  1999          1998          1997
               ---------              ------------- ------------  ------------
   <S>                                <C>           <C>           <C>
   Lucent Technologies, Inc. (3).....        16%           *             *
   Tellabs Operations, Inc. (2)......        13%          21%           16%
   Nortel Communications (4).........        13%           *             *
</TABLE>
--------
 * Below 10% of the Company's total revenues.
(1) Columbia Technology and Insight Electronics are distributors of our
    products to various end-users, none of which comprised more than 10% of the
    Company's total revenues during the periods 1998 and 1997. In 1999 a
    portion of the Lucent Technologies products were shipped through Insight
    Electronics, Inc.
(2)  The Company's sales to Tellabs during 1999 were made through Arrow which
     also shipped products to Nortel Communications, Inc. Sales to Tellabs
     through Arrow during 1998 represented 17% of the Company's total revenues.
     During 1998, sales to Tellabs were made through Reptron Electronics, Inc.
     and Arrow both Tellabs' designated distributors. The Company's sales to
     Tellabs during 1997 were made through Reptron, Tellabs' designated
     distributor.
(3)  Includes sales to Ascend Communications, which was acquired by Lucent
     Technologies during 1999. This percentage represents total shipments
     including those made directly and those made through distributors.
(4)  This represents total shipments including those made directly and those
     made through distributors.

                                       4
<PAGE>

Research and Development

   The Company believes that the continued introduction of new products in its
target markets is essential to its growth. As of December 31, 1999, the Company
had 105 full-time employees engaged in research and development efforts. The
Company believes that its research and development staffing will only
moderately increase in 2000. Expenditures for research and development in 1999,
1998 and 1997 were approximately $14.0 million, $11.1 million and $9.2 million,
respectively.

   All developments are carried out using ISO 9001 certified design processes
and the design tools/environment are continuously enhanced for improvement in
design, fabrication and verification of it products. The Company invests in
establishing and enhancing its design process, tools, methodology and
proprietary Tests Benches. From time to time, the Company acquires rights to
intellectual property from third parties to enhance its product lines. The
Company's internal research and development organization thoroughly reviews the
external development processes and the design of these products as part of its
quality assurance process.

Patents and Licenses

   The Company has 28 patents issued and 15 patent applications pending in the
U.S. Of the 28 issued patents, one is co-owned by ECI Telecom Ltd. and one is
co-owned by Siemens Telecommunications Systems Ltd. The Company has four
patents issued and 18 patent applications pending in Canada. The Company has
six patents issued in Taiwan, with one patent being co-owned by Siemens
Telecommunications Systems Ltd. The Company has three patents issued and five
patents pending in the People's Republic of China and one patent pending in
Hong Kong. The Company has 13 patent applications pending in selected countries
in the European Patent Office (EPO), two patents issued in France, Germany, and
the U.K., one patent issued in France, Germany, Italy and the U.K., and one
patent issued in Belgium, France, Germany, Italy, Spain, Sweden and the U.K. in
addition, the Company has five patent applications pending in Japan, and seven
patents issued and three patents pending in Israel. Further, the Company has
two patent applications pending under the Patent Cooperation Treaty (PCT) with
the possibility of filing in the EPO, Canada, China, Mexico, Norway, Japan and
Israel. None of the Company's domestic and foreign patents that have issued
will expire in the near future unless the Company chooses not to pay renewal
fees. The Company's oldest patent is not scheduled to expire for almost eight
years.

   The Company cannot guarantee that its patents will not be challenged or
circumvented by its competitors, nor can the Company be sure that pending
patent applications will ultimately be issued as patents. Under current law,
patent applications in the United States are maintained in secrecy until
patents are issued, and the right to a patent in the United States is
attributable to the first to invent, not the first to file a patent
application. In the process of obtaining foreign patents, patent applications
are published approximately 18 months after their priority (U.S.) filing date,
and the right to a patent is determined by the first to file an application.
The Company cannot be sure that its products or technologies do not infringe
patents that may be granted in the future pursuant to pending patent
applications or that its products do not infringe any patents or proprietary
rights of third parties. From time to time, the Company receives communications
from third parties alleging patent infringement. In the event that any relevant
claims of third-party patents are upheld as valid and enforceable, the Company
could be prevented from selling its products or could be required to obtain
licenses from the owners of such patents or be required to redesign its
products to avoid infringement. The Company cannot assure that such licenses
would be available or, if available, would be on terms acceptable to the
Company or that the Company would be successful in any attempts to redesign its
products or processes to avoid infringement. The Company's failure to obtain
these licenses or to redesign its products would have a material adverse effect
on the Company's business, financial condition and results of operations.

   The Company also has been granted registration of 11 trade or service marks
in the U.S., and it has nine more U.S. applications for trademarks awaiting
approval. The Company has also obtained three trademark registrations and has
one trademark awaiting approval under the European Trademark (ECT) procedure.


                                       5
<PAGE>

   The Company's ability to compete depends upon its ability to protect its
proprietary information through various means, including ownership of patents,
copyrights, mask work registrations and trademarks. While no intellectual
property right of the Company has been invalidated or declared unenforceable,
there can be no assurance that such rights will be upheld in the future. The
Company believes that, in view of the rapid pace of technological change in the
semiconductor industry, the technical experience and creative skills of its
engineers and other personnel are the most important factors in determining the
Company's future technological success.

   TranSwitch has entered into various license agreements for product or
technology exchange. The purpose of these licenses has, in general, been to
obtain second sources for standard products or to convey or receive rights to
certain proprietary or patented cores, cells or other technology. In March
1995, the Company entered into an agreement with StrataCom, Inc., whereby the
Company obtained the right to use intellectual property covered by two
StrataCom, Inc. patents.

   The Company sells its products into the telecommunications industry, an
industry whose products are subject to various standards which are agreed upon
by recognized industry standards committees. Where applicable, the Company
designs its product to be in conformity with these standards. The Company has
received and expects to continue to receive, in the normal course of business,
communications from third parties stating that if certain of TranSwitch's
products meet a particular standard, these products may infringe one or more
patents of that third party. After a review of the circumstances of each
communication, the Company in its discretion and upon the advice of counsel has
taken or may take in the future one of the following courses of action: the
Company may negotiate payment for a license under the patent or patents that
may be infringed; the Company may use its technology and/or patents to
negotiate a cross-license with the third party; or the Company may decline to
obtain a license on the basis that it does not infringe the claimant's patent
or patents, or that such patents are not valid or other basis. The Company
cannot assure that licenses for any of these patents will be available to the
Company on reasonable terms or that the Company would prevail in any litigation
seeking damages or expenses from the Company or to enjoin the Company from
selling its products on the basis of any of the alleged infringements.

Manufacturing and Quality

   TranSwitch's manufacturing objective is to produce reliable, high quality
devices cost-competitively. To this end, the Company seeks to differentiate
itself by:

  -- maximizing the reliability and quality of its products;

  -- achieving on-time delivery of its products to its customers;

  -- minimizing capital and other resource requirements by subcontracting
     capital-intensive manufacturing; and

  -- achieving a gross margin commensurate with the value of its products.

   Effective June 25, 1997, the Company was registered by TUV Rheinland of
North America, Inc. as complying with the requirements of ISO-9001.

   All of the Company's VLSI devices are manufactured by established
independent foundries. This approach permits the Company to focus on its design
strengths, minimize fixed costs and capital expenditures and access diverse
manufacturing technologies. Currently, the Company utilizes three foundries,
two of which are located in the U.S. and the third in Taiwan, to process its
wafers: Texas Instruments Incorporated (TI), LSI Logic Corporation (including
Symbios Logic Inc., which it acquired) in the U.S. and Taiwan Semiconductor
Manufacturing Company Limited (TSMC) in Taiwan. Foundries are required to have
qualified and reliable processes. The selection of a foundry for a specific
device is based on availability of the required process technology and the
foundry's capability to support the particular set of tools used by TranSwitch
for that device.


                                       6
<PAGE>

   Currently, TI manufactures all of the Company's BiCMOS devices. The Company
entered into a foundry agreement with TI in December 1995, pursuant to which
the Company received access to TI's process technology through 2000. The
Company also has an agreement with TSMC that guarantees the Company a minimum
capacity level through 2004, and in return the Company has agreed to purchase
unutilized commitment below an agreed minimum level. See also "Note 11 to
Notes to Consolidated Financial Statements."

   There are certain significant risks associated with the Company's reliance
on outside foundries, including:

  -- the lack of assured wafer supply and control over delivery schedules;

  -- the unavailability of or delays in obtaining access to key process
     technologies; and

  -- limited control over quality assurance, manufacturing yields and
     production costs.

   In addition, the manufacture of integrated circuits is a highly complex and
technologically demanding process. Although the Company has undertaken to
diversify its sources of semiconductor device supply and works closely with
all its foundries to minimize the likelihood of reduced manufacturing yields,
the Company's foundries have from time to time experienced lower than
anticipated manufacturing yields, particularly in connection with the
introduction of new products and the installation and start up of new process
technologies. Reduced yields have at times adversely affected the Company's
operating results.

Competition

   The semiconductor industry is intensely competitive and is characterized by
the following:

  -- price erosion;

  -- rapid technological change;

  -- shortage in fabrication capacity;

  -- heightened international competition in many markets; and

  -- unforeseen manufacturing yield problems.

   The communications and data communications industries, which are the
primary target markets for TranSwitch, are also becoming intensely competitive
because of deregulation and heightened international competition.

   The Company's competition consists of suppliers of similar products from
the United States as well as other countries, including internal competition
from semiconductor divisions of vertically integrated companies such as IBM
Corporation, Lucent Technologies, NEC Corporation and Siemens AG. New entrants
are also likely to attempt to obtain a share of the market for the Company's
current and future products.

   The Company's principal competitors in the asynchronous and SONET/SDH areas
are Applied Micro Circuits Corporation, Conexant Systems Inc., Crystal
Semiconductor Corporation, Dallas Semiconductor Corporation, EXAR Corporation,
Lucent Technologies Inc., National Semiconductor Corporation, PMC-Sierra Inc.,
Texas Instruments Incorporated, Triquint Semiconductor Corporation, Vitesse
Semiconductor Corporation and VLSI Technology, Inc. In addition, there are a
number of ASIC vendors, including AMI Industries, Inc., LSI Logic Corp., and
STM Microelectronics Group, who compete with the Company by supplying
customer-specific products to OEMs. In the ATM area, the Company's principal
competitors include all the vendors mentioned above and, in addition, Advanced
Micro Devices, Inc., Integrated Device Technology, Inc. and MMC Networks, Inc.
Numerous other domestic and international vendors have announced plans for
entering this market.

                                       7
<PAGE>

   TranSwitch believes that the principal bases of competition in the
semiconductor industry include:

  -- product definition;

  -- product design;

  -- test capabilities;

  -- reliability;

  -- price;

  -- functionality;

  -- time-to-market; and

  -- reputation.

   The Company believes that it competes favorably with respect to these
factors. TranSwitch also believes that its competitive strengths include the
distribution channels it has established, the Company's workforce of highly
experienced digital and mixed-signal circuit designers with strong systems
architecture skills and its proprietary design and development tools, including
its proprietary simulations and testing software and its library of analog and
digital blocks and cells.

   The ability of the Company to compete successfully in the rapidly evolving
area of high performance integrated circuit technology depends on factors both
within and outside its control, including:

  -- success in designing and subcontracting the manufacture of new products
     that implement new technologies;

  -- protection of Company products by effective utilization of intellectual
     property laws;

  -- product quality;

  -- reliability;

  -- price;

  -- efficiency of production;

  -- the pace at which customers incorporate the Company's integrated
     circuits into their products;

  -- success of competitors' products; and

  -- general economic conditions.

Backlog

   As of December 31, 1999, the Company's backlog was $21.7 million, as
compared to $14.0 million as of December 31, 1998. Backlog represents firm
orders anticipated to be shipped within the next 12 months. The Company's
business and, to a large extent, that of the entire semiconductor industry is
characterized by short-term order and shipment schedules. Since orders
constituting the Company's current backlog are subject to changes in delivery
schedules or to cancellation at the option of the purchaser without significant
penalty, backlog is not necessarily an indication of future revenue.

Employees

   As of December 31, 1999, the Company had 203 full time employees. The
Company's employees are not represented by any collective bargaining agreement,
and the Company has never experienced a work stoppage. The Company believes
that its employee relationships are good.

                                       8
<PAGE>

ITEM 2. PROPERTIES

Facilities

   The Company's headquarters are located in a suburban office park in Shelton,
Connecticut, where it leases approximately 60,000 square feet in a four-story
office building. Product development and all final inspection, shipping,
marketing and administration activities are located at this facility.
Approximately 90% of the existing space is fully utilized and the Company
expects to lease additional space in 2000. The lease is due to expire in
November 2007. The Company also leases approximately 1,200 square feet in
Raleigh, North Carolina where additional product development efforts take
place. In September 1997, the Company leased approximately 3,200 square feet in
Stoneham, Massachusetts for product development and sales support. The Company
leases a 1,400 square foot sales and support facility in San Jose, California.
The Company also maintains a small sales office in Brussels, Belgium. In
January 1997, the Company opened a new leased facility of 2,000 square feet in
Taipei, Taiwan for product development and sales support, and in May 1998, the
Company opened a 5,000 square-foot facility in New Delhi, India for product
development.

ITEM 3. LEGAL PROCEEDINGS

   None.

ITEM 4. SUBMISSION OF MATTERS TO A VOTE OF SECURITY-HOLDERS

   No matters were submitted to a vote of security holders during the three
months ended December 31, 1999.

                                       9
<PAGE>

                                    PART II

ITEM 5. MARKET FOR REGISTRANT'S COMMON EQUITY AND RELATED STOCKHOLDER MATTERS

   The Company's Common Stock has been quoted on the Nasdaq National Market
tier of The Nasdaq Stock Market under the symbol "TXCC" since its initial
public offering on June 14, 1995. The following table sets forth, for the
periods indicated, the range of quarterly high and low sale information for the
Company's Common Stock as reported on the Nasdaq National Market:

<TABLE>
<CAPTION>
                                                                  High     Low
                                                                 Sale(1) Sale(1)
                                                                 ------- -------
   <S>                                                           <C>     <C>
   1998
   First Quarter................................................ $ 5.56  $ 3.33
   Second Quarter...............................................   6.83    4.78
   Third Quarter................................................   8.89    5.72
   Fourth Quarter...............................................  20.11    4.89
   1999
   First Quarter................................................ $21.22  $13.22
   Second Quarter...............................................  31.75   15.56
   Third Quarter................................................  43.33   26.83
   Fourth Quarter...............................................  48.41   24.79
</TABLE>
--------
(1)  Prices adjusted to reflect a 3 for 2 stock split in the form of a dividend
     on June 8, 1999 and a 3 for 2 stock split in the form of a dividend on
     January 11, 2000.

   As of February 29, 2000, there were approximately 222 holders of record and
approximately 20,000 of beneficial shareholders of the Company's Common Stock.

   The Company has never paid cash dividends on its Common Stock. The Company
currently intends to retain earnings, if any, for use in its business and does
not anticipate paying any cash dividend in the foreseeable future. In addition,
the Company's line of credit loan agreement prohibits the payment of cash
dividends without prior bank approval. Any future declaration and payment of
dividends will be subject to the discretion of the Company's Board of
Directors, will be subject to applicable law and will depend upon the Company's
results of operations, earnings, financial condition, contractual limitations,
cash requirements, future prospects and other factors deemed relevant by the
Company's Board of Directors.

                                       10
<PAGE>

ITEM 6. SELECTED FINANCIAL DATA

   The selected data presented below under the captions, "Selected Statement of
Earnings Data" and Selected Balance Sheet Data" are as of the end of each of
the years in the five year period ended December 31, 1999, are derived from the
Consolidated Financial Statements of the Company which financial statements
have been audited by KPMG LLP, independent certified public accountants. The
consolidated financial statements as of December 31, 1999 and 1998 and for each
of the years in the three year period ended December 31, 1999 and the reports
thereon are included elsewhere in this document.

<TABLE>
<CAPTION>
                                             Year Ended December 31,
                                       --------------------------------------
                                        1999    1998   1997    1996     1995
                                       ------- ------ ------  -------  ------
                                         Amounts presented in thousands,
                                              except per share data
<S>                                    <C>     <C>    <C>     <C>      <C>
Selected Statement of Earnings Data:
Total revenues........................ $71,407 44,169 27,084   19,650  17,466
Gross profit..........................  46,964 27,524 15,830    5,844  10,071
Net income (loss) (3).................  25,154  6,003 (1,873) (10,077) (1,773)
Diluted income (loss) per share (1)
 (2) (3).............................. $   .62    .18   (.07)    (.38)   (.08)
Shares used in calculation of diluted
 income (loss) per share..............  40,545 33,488 27,342   26,440  22,640
</TABLE>

<TABLE>
<CAPTION>
                                                      December 31,
                                          ------------------------------------
                                            1999    1998   1997   1996   1995
                                          -------- ------ ------ ------ ------
<S>                                       <C>      <C>    <C>    <C>    <C>
Selected Balance Sheet Data:
Cash, cash equivalents and short term
 investments............................. $ 75,317 27,196 21,618 12,688 17,250
Working capital..........................   91,803 33,758 25,648 14,650 21,811
Total assets.............................  159,894 47,809 36,589 23,311 32,670
Stockholders' equity..................... $151,193 40,354 30,161 17,299 26,706
</TABLE>
--------
(1)  Gives effect to the mandatory conversion of all then outstanding Preferred
     Stock into 7,009,742 shares of Common Stock on completion of the Company's
     initial public offering in June 1995.
(2)  1995 through 1999 revised to reflect a 3 for 2 stock split in the form of
     a dividend on June 8, 1999 and a 3 for 2 stock split in the form of a
     dividend on January 11, 2000.
(3)  During the third quarter of 1999 the Company concluded that it is more
     likely than not that substantially all of its net deferred tax assets will
     be realized. Accordingly, the Company reversed the valuation allowance for
     those deferred tax assets, which resulted in the recording of a net tax
     benefit of $2.9 million for the year ended December 31, 1999.

                                       11
<PAGE>

ITEM 7. MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS
        OF OPERATIONS

   The following Management's Discussion and Analysis of Financial Condition
and Results of Operations contains forward-looking statements that involve
risks and uncertainties. When used in this document, the words, "intend,"
"anticipate," "believe," "'estimate," "plan" and "'expect" and similar
expressions as they relate to the Company are included to identify forward-
looking statements. The Company's actual results could differ materially from
those anticipated in these forward-looking statements as a result of certain
factors, including those set forth under "Certain Factors That May Affect
Future Results." This discussion should be read in conjunction with the
Consolidated Financial Statements and the notes thereto included in this Report
at Item 14.

Overview

   TranSwitch Corporation commenced its operations in April 1988. Since
incorporation, TranSwitch has designed, sourced and marketed high-speed VLSI
semiconductor devices for public and private network applications worldwide.
TranSwitch shipped its first product in 1990 and has increased its volume of
shipments over the last ten years. TranSwitch's product development efforts
have been focused on devices that meet the needs of public and private network
telecommunications and data communications equipment providers that serve the
worldwide public network, Internet and corporate wide area network markets. The
Company's devices are compliant with established standards in these markets,
including SONET/SDH, asynchronous and ATM.

   The Company derives its revenues from product sales principally to domestic
and international telecommunications and data communications equipment OEMs and
to distributors. Revenues are recognized on product shipment. Agreements with
certain distributors provide price protection and return and allowance rights.
In certain cases, the Company works with network equipment OEMs during their
system design phase with the goal of having TranSwitch's products designed into
the OEMs' products. The Company's sales cycle often extends over more than one
year because of the long lead times between the OEM's design to the start of
volume shipments. The Company incurs product research and development expenses
well before the generation of substantial revenues from product sales to OEMs.
A significant portion of the Company's total revenues has been, and is
anticipated to be, derived from foreign sales. All foreign sales are currently
denominated in U.S. dollars. The Company's cost of revenues consists primarily
of the purchase cost of finished VLSI devices produced by third party
semiconductor manufacturers and amortization of product licenses. The Company
intends to continue to outsource all of its VLSI device fabrication
requirements.

   As of December 31, 1999, the Company had retained earnings of $1.2 million.
The Company's operating results are subject to quarterly and annual
fluctuations as a result of several factors that could materially and adversely
affect profitability. These factors include, among others:

  --the timing and cancellations of the Company's customers' orders;

  --market acceptance of products of both the Company and its customers;

  --the level of orders that are received and can be shipped in a quarter;

  --the timing and provision of price protection and returns from the
   Company's distributors;

  --availability and cost of semiconductor foundry capacity and materials;

  --fluctuations in manufacturing yields;

  --changes in product mix;

  --the Company's ability to introduce new products and technologies on a
   timely basis;

                                       12
<PAGE>

  --the introduction of products and technologies by the Company's
   competitors;

  --the timing of the Company's investments in research and development;

  --whether TranSwitch's customers purchase through a distributor or directly
   from the Company;

  --competitive pressures on selling prices; and

  --general economic conditions.

Results of Operations

 Years Ended December 31, 1999, 1998 and 1997

   Total Revenues. In 1999, the Company reported revenues of $71.4 million an
increase of 61.5% over 1998. The increase was driven by the strength in the
Company's Asynchronous and ATM product lines. In 1998, the Company reported
revenues of $44.2 million, an increase of 63.1% over 1997 where revenues were
$27.1 million. The increase was primarily driven by the strength in the
Company's SONET product lines. The Company did not derive any revenue in 1999
or 1998 attributable to product license and royalty fees.

   In 1999, Insight Electronics, Inc. and Arrow Electronics, distributors for
the Company accounted for 34% and 19% of revenue, respectively. End users
Lucent Technologies, Inc. Tellabs Operations, Inc., and Nortel Communications
accounted for 16%, 13% and 13% of total revenues, respectively in 1999. In
1998, Insight Electronics, Inc., Columbia Technology (both distributors selling
to various end users, none of which comprise more than 10% of the Company's
total revenues) and Tellabs Operations, Inc. accounted for 20%, 15% and 21% of
total revenues, respectively.

   Foreign sales, consisting primarily of sales to customers in Europe, the
Middle East and the Far East, constituted 30%, 46% and 33% of total revenues in
1999, 1998 and 1997, respectively.

   Gross profit. Gross margin in 1999 increased to 65.8% from 62.3% in 1998.
The increase in gross margin from 1998 is primarily a result of the continued
reduction in costs of products achieved by meeting higher volume milestones
established by its foundries. Gross margin in 1998 increased to 62.3% from
58.4% in 1997. The increase in gross margin from 1998 is primarily a result of
the reduction in costs of products, achieved by meeting higher volume
milestones established by its foundries.

   In 1999, gross profit increased to $47.0 million from $27.5 million in 1998,
a function of the continued increase in overall volume and the improvement in
the gross margin. In 1998, gross profit increased to $27.5 million from $15.8
million in 1997, a function of the increase in overall volume and the
improvement in the gross margin over 1997.

   Research and development. In 1999, research and development expenses were
$14.0 million, or 19.6% of total revenues, an increase of 26.8% over 1998
expenditures. In 1998, research and development expenses were $11.1 million, or
25.0% of total revenues, an increase of 20.2% over 1997 expenditures of $9.2
million or 33.9% of total revenues. The increases were primarily attributable
to increases in staff and in non-recurring engineering charges related to the
introduction of new products during 1999 and 1998. The Company believes that
the continued introduction of new products is essential to its competitiveness
and is committed to continuing its investment in research and development. The
Company believes that its research and development expenses will increase in
absolute dollars in the future as it continues to add products to all of its
product lines.

   Marketing and sales. In 1999, marketing and sales expenses increased 37.9%
to $12.0 million, and represented 16.8% of total revenues. In 1998, marketing
and sales expenses increased 30.2% to $8.7 million or 19.7% of total revenues
over 1997 expenses of $6.7 million or 24.7% of total revenues. The increases
were the

                                       13
<PAGE>

result of the increase in variable cost of commissions on the increased total
revenues and additional staff in 1999 and 1998. The Company anticipates that it
will continue to incur higher marketing and sales expenses in absolute dollars
as it expands its marketing and sales efforts.

   General and administrative. In 1999, general and administrative expenses
increased 34.1% over 1998 to $3.4 million, or 4.7% of total revenues. In 1998,
general and administrative expenses increased 10.0% over 1997 to $2.5 million,
or 5.7% of total revenues over 1997 expenses of $2.3 million or 8.5% of total
revenues. The increase in the overall expenses was the result of TranSwitch's
continued investment in the general and administrative area.

Income taxes

   During the third quarter of 1999, the Company concluded that it is more
likely than not that substantially all of its net deferred tax assets will be
realized. Accordingly, the Company reversed its valuation allowance for net
deferred tax assets, which contributed to the resulting of a net tax benefit of
$2.9 million for the year ended December 31, 1999. The resulting 1999 effective
tax rate of (13%) compares to a 4.5% tax rate for 1998. The 1998 tax rate was
attributable primarily to state taxes. For 2000, the Company expects the
effective tax rate to approximate 38%.

Liquidity and Capital Resources

   The Company has financed its operations and met its capital requirements
since it was incorporated in 1988 primarily through private placements of
preferred stock, borrowings from a working capital line of credit and equipment
financing line of credit from Silicon Valley Bank, an initial public offering
of its common stock in June 1995 and cash generated from its operations. In
October 1997, the Company received net proceeds of $13.7 million in cash in
connection with a private placement of its Series A Convertible Preferred
Stock. All such shares had been converted into shares of common stock as of
September 30, 1998. On February 9, 1999 and March 16, 1999, the Company
completed a follow-on public offering and raised $68.4 million, net of
commissions, and issued 4,398,750 million shares of its common stock (adjusted
for a 3 for 2 stock split on June 8, 1999 and a 3 for 2 stock split on January
11, 2000).

   The Company's principal sources of liquidity as of December 31, 1999
consisted of $75.3 million in cash, cash equivalents and short-term
investments, $36.0 million in long term investments and $10.0 million available
under the Company's working capital line of credit and equipment line of credit
provided by Silicon Valley Bank. As of December 31, 1999 the Company had no
outstanding balance under these lines of credit. Pursuant to the working
capital and equipment financing agreements with Silicon Valley Bank, the
Company is restricted from further pledging its assets or granting additional
security interests in such assets.

   In 1999, the Company generated $17.3 million in cash from its operations,
the result of net income of $25.2 million, $3.2 million of depreciation and
amortization and $0.1 million of non-cash expense, offset by a net increase of
$4.9 million in deferred income taxes and $6.2 million in working capital. In
1998, the Company generated $6.7 million in cash from operating activities, the
result of a net income of $6.0 million, $2.4 million for depreciation and
amortization and non-cash expense of $0.4 million, offset by an increase in
working capital of $2.1 million.

   Net cash provided by financing activities consists of proceeds from the
exercise of stock options and warrants of $7.1, $3.9 and $0.7 million in 1999,
1998 and 1997, respectively, and net proceeds from the issuance of preferred
stock of $13.7 million in 1997 and a follow on public offering in 1999 of $68.4
million, net of commissions.

   The Company believes that its existing cash resources and cash generated
from operations, will fund necessary purchases of capital equipment and provide
adequate working capital through the end of 2000.

                                       14
<PAGE>

However, there can be no assurance that events in the future will not require
the Company to seek additional capital sooner or, if so required, that such
capital will be available on terms favorable or acceptable to the Company, if
at all.

   Inflation has not had a significant impact on the Company's operations.

Certain Factors That May Affect Future Results

   From time to time, information provided by the Company, statements made by
its employees, or information included in its filings with the Securities and
Exchange Commission (including this Form 10-K) may contain statements that are
not historical facts, so-called "forward-looking statements," which involve
risks and uncertainties. Such forward-looking statements are made pursuant to
the safe harbor provisions of Section 21E of the Securities Exchange Act of
1934, as amended. In particular, statements in "Item 1. Business" relating to
product introductions and the availability of third party VLSI fabrication
facilities, in "Item 2. Properties" concerning the adequacy of the Company's
current facility space, and in "Item 7. Management's Discussion and Analysis of
Financial Condition and Results of Operations" relating to total revenues, the
anticipated level of foreign sales, anticipated increases in research and
development and sales and marketing expenses and the availability of capital
for working capital and for the purchase of capital equipment, may be forward-
looking statements. The Company's actual future results may differ
significantly from those stated in any forward-looking statements. Factors that
may cause such differences include, but are not limited to, the factors
discussed below. Each of these factors, and others, are discussed from time-to-
time in the Company's filings with the Securities and Exchange Commission.

   Potential Fluctuations in Operating Results. The Company's quarterly and
annual operating revenues, expenses and operating results may fluctuate due to
a number of factors including:

  --the timing and cancellation of customer orders;

  --market acceptance of the Company's and customers' products;

  --competitive pressures on selling prices; and

  --general economic conditions.

   Management of Growth and Dependence on Key Personnel. TranSwitch must
attract and retain highly qualified and well-trained personnel, including
senior managers. Competition for such employees is intense, and it may become
increasingly difficult for the Company to hire and retain such personnel.

   TranSwitch Depends on a Few Outside Fabrication Facilities. The Company does
not own or operate a Very Large Scale Integrated (VLSI) circuit fabrication
facility, and depends upon three foundries for most of its semiconductor device
requirements. The Company cannot be certain that it will be able to renew or
maintain contracts with these foundries on terms as favorable as current
contract terms. There are other significant risks associated with reliance on a
few outside foundries, including:

  --the lack of assured semiconductor wafer supply and control over delivery
   schedules;

  --the unavailability of, or delays in obtaining access to, key process
   technologies; and

  --limited control over quality assurance, manufacturing yields and
   production costs.

   Dependence on Telecommunications, Internet and Wide Area Communications
Markets. The Company derives virtually all of its product revenues from sales
of products for the telecommunications, Internet and wide area communications
markets, which are characterized by intense competition, rapid technological
change and short product life cycles. Although the telecommunications, Internet
and wide area communications equipment markets have grown rapidly in the last
few years, they may not continue to grow, or a significant slowdown in these
markets may occur.

                                       15
<PAGE>

   Dependence on New Products; Risk of Product Development Delays. The
development of new VLSI devices is highly complex, and from time-to-time, the
Company has experienced delays in completing the development of new products.

   Customer Concentration. Historically, a relatively small number of customers
have accounted for a significant portion of the Company's total revenues in any
particular period and probably will continue to do so.

   TranSwitch's Success Depends on Intellectual Property. The Company's success
depends in part on its ability to obtain patents and licenses and to preserve
other intellectual property rights covering its products and development and
testing tools. The Company cannot ensure that:

  --patents be will issued from currently pending or future applications;

  -- its existing patents or any new patents will be sufficient in scope or
     strength to provide meaningful protection or any commercial advantage;

  --foreign intellectual property laws will protect the Company's
   intellectual property rights; or

  -- others will not independently develop similar products, duplicate the
     Company's products or design around any patents issued to the Company.

   In addition, the Company may be unknowingly infringing on the proprietary
rights of others and may be liable for that infringement, which could result in
significant liability.

   Competition. The semiconductor industry is intensely competitive and is
characterized by factors likely to result in pricing pressures on the Company's
products.

   Foreign Sales. TranSwitch expects foreign sales to continue to account for a
significant percentage of revenues. A significant portion of total revenues
will therefore be subject to risks associated with foreign sales.

   The Semiconductor Industry. TranSwitch provides semiconductor devices to
telecommunications and data communications OEMs. The semiconductor industry is
highly cyclical and has been subject to significant economic downturns at
various times.

   Year 2000 update. To date the Company has not experienced any disruptions
either internally or externally from its suppliers, service providers or
customers that could be attributed to the Year 2000 computer issues. Total
expenditures, exclusive of software and systems that are being replaced or
upgraded in the normal course of business, was approximately $120,000, which is
consistent with prior estimates.

ITEM 8. CONSOLIDATED FINANCIAL STATEMENTS AND SUPPLEMENTARY DATA

   The information required by this Item is contained in the financial
statements and schedule set forth in Item 14 (a) of this Form 10-K.

ITEM 9. CHANGES IN AND DISAGREEMENTS WITH ACCOUNTANTS ON ACCOUNTING AND
        FINANCIAL DISCLOSURE

   There has been no change of accountants nor any disagreements with
accountants on any matter of accounting principles or practices or financial
statement disclosure required to be reported under this Item.

                                       16
<PAGE>

                                    PART III

ITEM 10. DIRECTORS AND EXECUTIVE OFFICERS OF THE REGISTRANT

   The information required by this Item is incorporated herein by reference to
the information in the sections entitled "Election of Directors," "Occupations
of Directors and Executive Officers," and "Compensation and Other Information
Concerning Directors and Officers" contained in the Company's definitive proxy
statement to be filed with the Securities and Exchange Commission not later
than 120 days after the close of the fiscal year ended December 31, 1999.

ITEM 11. EXECUTIVE COMPENSATION

   The information required by this Item is incorporated herein by reference to
the information in the section entitled "Compensation and Other Information
Concerning Directors and Officers" contained in the Company's definitive proxy
statement to be filed with the Securities and Exchange Commission not later
than 120 days after the close of the fiscal year ended December 31, 1999.

ITEM 12. SECURITY OWNERSHIP OF CERTAIN BENEFICIAL OWNERS AND MANAGEMENT

   The information required by this Item is incorporated herein by reference to
the information in the section entitled "Management and Principal Stockholders"
contained in the Company's definitive proxy statement to be filed with the
Securities and Exchange Commission not later than 120 days after the close of
the fiscal year ended December 31, 1999.

ITEM 13. CERTAIN RELATIONSHIPS AND RELATED TRANSACTIONS

   The information required by this Item is incorporated herein by reference to
the information in the section entitled "Compensation and Other Information
Concerning Directors and Executive Officers" contained in the Company's
definitive proxy statement to be filed with the Securities and Exchange
Commission not later than 120 days after the close of the fiscal year ended
December 31, 1999.

                                       17
<PAGE>

                                    PART IV

ITEM 14. EXHIBITS, FINANCIAL STATEMENT SCHEDULES, AND REPORTS ON FORM 8-K

(a) 1.Consolidated Financial Statements

     For the following financial information included herein, see Index on
  page F-1:

      Independent Auditors' Report.

      Consolidated Balance Sheets as of December 31, 1999 and December 31,
       1998.

      Consolidated Statements of Operations for each of the years in the
       three year period ended December 31, 1999.

      Consolidated Statements of Stockholders' Equity (Deficit) for each of
       the years in the three year period ended December 31, 1999.

      Consolidated Statements of Cash Flows for each of the years in the
       three year period ended December 31, 1999.

      Notes to Consolidated Financial Statements.

  2. Financial Statement Schedule

     The following financial statement schedule is included herein:

       Schedule II Valuation and Qualifying Accounts.

     All other schedules are not submitted because they are not applicable,
  not required or because the information is included in the Consolidated
  Financial Statements or Notes to Consolidated Financial Statements.

                                       18
<PAGE>

    3.  Exhibits

<TABLE>
<CAPTION>
   Exhibit
   Number                                Description
   -------                               -----------
 <C>         <S>
   3.1*      Amended and Restated Certificate of Incorporation of the Company

   3.2*      By-laws, as amended and restated, of the Company

   4.1*      Specimen certificate representing the Common Stock

  10.1*      1989 Stock Option Plan

  10.2++     Third Amended and Restated 1995 Stock Plan as amended

  10.3*      1995 Employee Stock Purchase Plan

  10.4++     1995 Non-Employee Director Stock Option Plan, as amended

  10.5*      Form of Incentive Stock Option Agreement for 1989 Stock Option
             Plan

  10.6*      Form of Non-Qualified Stock Option Agreement for 1989 Stock Option
             Plan

  10.7***    Form of Incentive Stock Option Agreement under the 1995 Stock Plan
             of the Company

  10.8***    Form of Non-Qualified Stock Option Agreement under the 1995 Stock
             Plan of the Company

  10.9***    1995 Employee Stock Purchase Plan Enrollment/Authorization Form of
             the Company

  10.10***   Form of Non-Qualified Stock Option Agreement under the 1995 Non-
             Employee Director Stock Option Plan of the Company

 #10.11*     Agreement with Texas Instruments Incorporated

  10.12*     Authorized Distributor Agreement with Insight Electronics, Inc.

  10.13*     Development Agreement with Connecticut Innovations, Incorporated

  10.14***** Lease Agreement, as amended, with Robert D. Scinto

  10.15++++  Amended and Restated Promissory Note (Working Capital Line of
             Credit) with Silicon Valley Bank

  10.16++++  Amended and restated Promissory Note (Equipment Line of Credit)
             with Silicon Valley Bank

  10.17*     Commitment Letter, as amended, from Silicon Valley Bank

  10.18*     Security Agreement with Silicon Valley Bank

  10.19+++   Silicon Valley Bank Loan Modification Agreement

  10.20*     Development and License Agreement with Adaptive Corporation

  10.21*     OEM Agreement for Acquisition of IBM Products with International
             Business Machines Corporation

 #10.22*     License Agreement with StrataCom, Inc.

 #10.23****  Agreement with Texas Instruments Incorporated

 #10.24****  Integrated Circuit Foundry Agreement with Texas Instruments
             Incorporated

  10.25++++  Silicon Valley Bank Sixth Loan Modification Agreement

  10.26++++  Silicon Valley Bank Negative Pledge Agreement

  21.1++++   Subsidiaries of the Company

  23.1**     Consent of KPMG LLP

  27.1**     Financial Data Schedule
</TABLE>
--------
#    Confidential treatment obtained as to certain portions.
*    Previously filed as an exhibit to the Company's Registration Statement on
     Form S-1 (File No. 33-91694) and incorporated herein by reference.

                                       19
<PAGE>

+    Previously filed as an exhibit to the Company's Registration Statement on
     Form S-3 (File No. 333-40897) and incorporated herein by reference.
++   Previously filed as an exhibit to the Company's Definitive Proxy Statement
     on Schedule 14A dated April 26, 1999 and incorporated herein by reference.
+++  Previously filed as an exhibit to the Company's Form 10-Q for the quarter
     ended September 30, 1997 and incorporated herein by reference.
++++ Previously filed as an exhibit to the Company's Annual Report on Form 10-K
     for the fiscal year ended December 31, 1998 and incorporated by reference.
**   Filed herewith.
***  Previously filed as an exhibit to the Company's Registration Statement on
     Form S-8 (File No. 33-94324) and incorporated herein by reference.
**** Previously filed as an exhibit to the Company's Annual Report of Form 10-K
     for the fiscal year ended December 31, 1995
***** Previously filed as an exhibit to the Company's Annual Report on Form 10-
      K for the fiscal year ended December 31, 1997 and incorporated herein by
      reference.

(b) Reports on Form 8-K

     No reports on Form 8-K were filed by the Company during the fourth
  quarter ended December 31, 1999.

(c) Exhibits

     The Company hereby files as exhibits to this Form 10-K, those exhibits
  listed in Item 14 (a) (3) above.

(d) Financial Statement Schedule

     The Company hereby files as a financial statement schedule to this Form
  10-K, the financial statement schedule listed in Item 14(a) (2) above.

                                       20
<PAGE>

                                   SIGNATURES

   Pursuant to the requirements of Section 13 or 15(d) of the Securities
Exchange Act of 1934, the Company has duly caused this report to be signed on
its behalf by the undersigned, thereunto duly authorized.

   March 29, 2000
                                          TranSwitch Corporation

                                                    /s/ Dr. Santanu Das
                                          By: _________________________________
                                                      Dr. Santanu Das
                                                   Chairman of the Board,
                                               President and Chief Executive
                                                          Officer

                        POWER OF ATTORNEY AND SIGNATURES

   We, the undersigned officers and directors of TranSwitch Corporation, hereby
severally constitute and appoint Santanu Das and Michael McCoy, and each of
them singly, our true and lawful attorneys, with full power to them and each of
them singly, to sign for us in our names in the capacities indicated below, all
amendments to this report, and generally to do all things in our names and on
our behalf in such capacities to enable TranSwitch Corporation to comply with
the provisions of the Securities Exchange Act of 1934, as amended and all
requirements of the Securities and Exchange Commission.

   Pursuant to the requirements of the Securities Exchange Act of 1934, this
report has been signed below by the following persons on behalf of the Company
and in the capacities and on the dates indicated.

<TABLE>
<CAPTION>
          Name and Signature                    Title(s)                 Date
          ------------------                    --------                 ----
<S>                                    <C>                        <C>
       /s/ Dr. Santanu Das             Chairman of the Board,       March 29, 2000
______________________________________  President, and Chief
           Dr. Santanu Das              Executive Officer
                                        (principal executive
                                        officer)
      /s/ Michael F. Stauff            Senior Vice President,       March 29, 2000
______________________________________  Chief Financial Officer
          Michael F. Stauff             and Treasurer (principal
                                        financial and accounting
                                        officer)
     /s/ Alfred R. Boschulte           Director                     March 29, 2000
______________________________________
         Alfred R. Boschulte
   /s/ Dr. Steward S. Flaschen         Director                     March 29, 2000
______________________________________
       Dr. Steward S. Flaschen
     /s/ Dr. Ljubomir Micic            Director                     March 29, 2000
______________________________________
          Dr. Ljubomir Micic
</TABLE>

                                       21
<PAGE>

<TABLE>
<CAPTION>
          Name and Signature                    Title(s)                 Date
          ------------------                    --------                 ----
<S>                                    <C>                        <C>
       /s/ James M. Pagos              Director                     March 29, 2000
______________________________________
            James M. Pagos
   /s/ Dr. Albert E. Paladino          Director                     March 29, 2000
______________________________________
        Dr. Albert E. Paladino
      /s/ Erik van der Kaay            Director                     March 29, 2000
______________________________________
          Erik van der Kaay
</TABLE>

                                       22
<PAGE>

                                                                     SCHEDULE II

                             TranSwitch Corporation

                       Valuation and Qualifying Accounts
                                 (in thousands)

<TABLE>
<CAPTION>
                                             Additions
                                        -------------------
                                                                       Balance
                             Balance at Changes to Charges             at End
                             Beginning  Costs and  to Other              of
Description                  of Period   Expenses  Accounts Deductions Period
-----------                  ---------- ---------- -------- ---------- -------
<S>                          <C>        <C>        <C>      <C>        <C>
Year ended December 31,
 1999:
Allowance for losses on:
  Accounts receivable.......  $   261     $   47     $--     $    (14) $   294
  Inventory.................    1,543        539      --         (563)   1,519
Deferred tax valuation
 allowance..................   14,825        --       --      (13,992)     833
                              -------     ------     ----    --------  -------
                              $16,629     $  586     $--     $(14,569) $ 2,646
                              =======     ======     ====    ========  =======
Year ended December 31,
 1998:
Allowance for losses on:
  Accounts receivable.......  $   218     $   50     $--     $     (7) $   261
  Inventory.................    1,278        503      --         (238)   1,543
Deferred tax valuation
 allowance..................   14,867        --       --          (42)  14,825
                              -------     ------     ----    --------  -------
                              $16,363     $  553     $--     $   (287) $16,629
                              =======     ======     ====    ========  =======
Year ended December 31,
 1997:
Allowance for losses on:
  Accounts receivable.......  $   140     $  100     $--     $    (22) $   218
  Inventory.................    1,196        121      --          (39)   1,278
Deferred tax valuation
 allowance..................   13,384      1,483      --          --    14,867
                              -------     ------     ----    --------  -------
                              $14,720     $1,704     $--     $    (61) $16,363
                              =======     ======     ====    ========  =======
</TABLE>


                                       23
<PAGE>

                    TRANSWITCH CORPORATION AND SUBSIDIARIES

                               TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                                           Page
                                                                           ----
<S>                                                                        <C>
Independent Auditors' Report.............................................  F-2

Consolidated Balance Sheets as of December 31, 1999 and 1998.............  F-3

Consolidated Statements of Operations for Each of the Years in the Three-
 Year Period ended December 31, 1999.....................................  F-4

Consolidated Statements of Stockholders' Equity for Each of the Years in
 the Three-Year Period ended December 31, 1999...........................  F-5

Consolidated Statements of Cash Flows for Each of the Years in the Three-
 Year Period ended December 31, 1999.....................................  F-6

Notes to Consolidated Financial Statements...............................  F-7
</TABLE>

                                      F-1
<PAGE>

                          INDEPENDENT AUDITORS' REPORT

The Board of Directors and Shareholders
TranSwitch Corporation:

   We have audited the accompanying consolidated balance sheets of TranSwitch
Corporation and subsidiaries as of December 31, 1999 and 1998, and the related
consolidated statements of operations, stockholders' equity, and cash flows for
each of the years in the three-year period ended December 31, 1999. These
consolidated financial statements are the responsibility of the Company's
management. Our responsibility is to express an opinion on these consolidated
financial statements based on our audits.

   We conducted our audits in accordance with generally accepted auditing
standards. Those standards require that we plan and perform the audit to obtain
reasonable assurance about whether the financial statements are free of
material misstatement. An audit includes examining, on a test basis, evidence
supporting the amounts and disclosures in the financial statements. An audit
also includes assessing the accounting principles used and significant
estimates made by management, as well as evaluating the overall financial
statement presentation. We believe that our audits provide a reasonable basis
for our opinion.

   In our opinion, the consolidated financial statements referred to above
present fairly, in all material respects, the financial position of TranSwitch
Corporation and subsidiaries as of December 31, 1999 and 1998, and the results
of their operations and their cash flows for each of the years in the three-
year period ended December 31, 1999, in conformity with generally accepted
accounting principles.

Stamford, Connecticut
January 27, 2000

                                      F-2
<PAGE>

                    TRANSWITCH CORPORATION AND SUBSIDIARIES

                          Consolidated Balance Sheets
                       (in thousands, except share data)
                           December 31, 1999 and 1998

<TABLE>
<CAPTION>
                                                                1999    1998
                                                              -------- -------
<S>                                                           <C>      <C>
                           ASSETS
                           ------
Current assets:
  Cash and cash equivalents.................................. $ 55,264  24,243
  Short-term investments.....................................   20,053   2,953
  Accounts receivable, less allowance for doubtful accounts
   of $294 in 1999 and $261 in 1998..........................   12,368   7,624
  Inventories................................................    7,900   5,476
  Prepaid expenses and other current assets..................    4,919     917
                                                              -------- -------
    Total current assets.....................................  100,504  41,213
Investments..................................................   36,003     --
Property and equipment, net..................................    7,118   5,143
Deferred taxes--non-current..................................   11,567     --
Product licenses, net........................................    1,657   1,142
Other assets.................................................    3,045     311
                                                              -------- -------
    Total assets............................................. $159,894  47,809
                                                              ======== =======
            LIABILITIES AND STOCKHOLDERS' EQUITY
            ------------------------------------
Current liabilities:
  Accounts payable........................................... $  3,700   2,858
  Accrued expenses...........................................    1,454   1,218
  Accrued compensation.......................................    1,628   1,366
  Sales allowance reserve....................................    1,494   1,049
  Warranty reserve...........................................      425     661
  Product license fee payable, current portion...............      --      303
                                                              -------- -------
    Total current liabilities................................    8,701   7,455
Commitments and contingencies (note 11)
Stockholders' equity:
  Common stock $.001 par value; authorized 100,000,000
   shares; issued and outstanding 39,266,465 shares in 1999;
   and 33,026,696 shares in 1998.............................       39      33
  Additional paid-in capital.................................  149,958  64,279
  Retained earnings (accumulated deficit)....................    1,196 (23,958)
                                                              -------- -------
    Total stockholders' equity...............................  151,193  40,354
                                                              -------- -------
    Total liabilities and stockholders' equity............... $159,894  47,809
                                                              ======== =======
</TABLE>

          See accompanying notes to consolidated financial statements.

                                      F-3
<PAGE>

                    TRANSWITCH CORPORATION AND SUBSIDIARIES

                     Consolidated Statements of Operations
                    (in thousands, except per share amounts)

<TABLE>
<CAPTION>
                                                         Year ended December
                                                                 31,
                                                        -----------------------
                                                         1999     1998    1997
                                                        -------  ------  ------
<S>                                                     <C>      <C>     <C>
Revenues:
  Product revenues, net................................ $71,407  44,169  26,930
  Research and development contracts...................     --      --      154
                                                        -------  ------  ------
    Total revenues.....................................  71,407  44,169  27,084
Cost of revenues.......................................  24,443  16,645  11,254
                                                        -------  ------  ------
Gross profit...........................................  46,964  27,524  15,830
                                                        -------  ------  ------
  Operating expenses:
  Research and development.............................  14,014  11,053   9,194
  Marketing and sales..................................  11,979   8,699   6,681
  General and administrative...........................   3,374   2,516   2,288
                                                        -------  ------  ------
    Total operating expenses...........................  29,367  22,268  18,163
                                                        -------  ------  ------
Operating income (loss)................................  17,597   5,256  (2,333)
                                                        -------  ------  ------
Interest income (expense):
  Interest income......................................   4,667   1,121     641
  Interest expense.....................................      (2)    (90)   (181)
                                                        -------  ------  ------
    Interest income, net...............................   4,665   1,031     460
                                                        -------  ------  ------
Income (loss) before income taxes......................  22,262   6,287  (1,873)
Income tax (benefit) expense...........................  (2,892)    284     --
                                                        -------  ------  ------
Net income (loss)...................................... $25,154   6,003  (1,873)
                                                        =======  ======  ======
Basic earnings (loss) per share (note 9)............... $  0.66    0.19   (0.07)
                                                        =======  ======  ======
Diluted earnings (loss) per share (note 9)............. $  0.62    0.18   (0.07)
                                                        =======  ======  ======
</TABLE>


          See accompanying notes to consolidated financial statements.

                                      F-4
<PAGE>

                    TRANSWITCH CORPORATION AND SUBSIDIARIES

                Consolidated Statements of Stockholders' Equity
                       (in thousands, except share data)
<TABLE>
<CAPTION>
                                                                     Retained
                            Common stock    Convertible Additional   earnings
                          -----------------  preferred   paid-in   (accumulated
                            Shares   Amount    stock     capital     deficit)    Total
                          ---------- ------ ----------- ---------- ------------ --------
<S>                       <C>        <C>    <C>         <C>        <C>          <C>       <C>
Balance at December 31,
 1996...................  26,803,094  $ 27    $   --     $ 45,360    $(28,088)  $ 17,299
Shares of common stock
 issued in connection
 with the exercise of
 stock options and
 warrants, and the stock
 purchase plan..........     913,017   --         --          699         --         699
Issuance of convertible
 preferred stock, net of
 issuance costs.........         --    --      12,886         770         --      13,656
Deemed dividend on
 convertible preferred
 stock..................         --    --       1,471      (1,471)        --         --
Compensation related to
 issuance of stock
 options................         --    --         --          380         --         380
Net loss................         --    --         --          --       (1,873)    (1,873)
                          ----------  ----    -------    --------    --------   --------
Balance at December 31,
 1997...................  27,716,111    27     14,357      45,738     (29,961)    30,161
Shares of common stock
 issued in connection
 with the exercise of
 stock options and the
 stock purchase plan....   1,758,341     2        --        3,877         --       3,879
Deemed dividend on
 convertible preferred
 stock..................         --    --         143        (143)        --         --
Issuance costs for
 convertible preferred
 stock..................         --    --         --          (75)        --         (75)
Shares of common stock
 issued upon conversion
 of preferred stock.....   3,552,245     4    (14,500)     14,498         --           2
Compensation related to
 issuance of stock
 options................         --    --         --          384         --         384
Net income..............         --    --         --          --        6,003      6,003
                          ----------  ----    -------    --------    --------   --------
Balance at December 31,
 1998...................  33,026,696    33        --       64,279     (23,958)    40,354
Shares of common stock
 issued in connection
 with the exercise of
 stock options and the
 stock purchase plan....   1,841,019     2        --        7,103         --       7,105
Shares of common stock
 issued in connection
 with follow-on public
 offering...............   4,398,750     4        --       68,177         --      68,181
Tax benefits on stock
 options................         --    --         --        8,266         --       8,266
Reversal of deferred tax
 asset valuation
 allowance relating to
 tax benefits on stock
 options................         --    --         --        2,000         --       2,000
Compensation related to
 issuance of stock
 options................         --    --         --          133         --         133
Net income..............         --    --         --          --       25,154     25,154
                          ----------  ----    -------    --------    --------   --------
Balance at December 31,
 1999...................  39,266,465  $ 39    $   --     $149,958    $  1,196   $151,193
                          ==========  ====    =======    ========    ========   ========  ===
</TABLE>

          See accompanying notes to consolidated financial statements.

                                      F-5
<PAGE>

                    TRANSWITCH CORPORATION AND SUBSIDIARIES

                     Consolidated Statements of Cash Flows
                                 (in thousands)

<TABLE>
<CAPTION>
                                                    Years ended December 31,
                                                    --------------------------
                                                      1999     1998     1997
                                                    --------  -------  -------
<S>                                                 <C>       <C>      <C>
Cash flows from operating activities:
  Net income (loss)................................ $ 25,154  $ 6,003  $(1,873)
                                                    --------  -------  -------
  Adjustments required to reconcile net income
   (loss) to cash flows from operating activities:
    Depreciation and amortization..................    3,204    2,445    1,807
    Deferred income taxes..........................   (4,945)     --       --
    Stock compensation expense.....................      133      384      380
  Changes in assets and liabilities:
    (Increase) in accounts receivable..............   (4,744)  (3,096)  (1,635)
    (Increase) in inventories......................   (2,424)    (664)  (1,288)
    (Increase) in prepaids and other current
     assets........................................   (1,903)    (413)    (510)
    Increase (decrease) in accounts payable........      842    1,508     (455)
    Increase in accrued expenses and other current
     liabilities...................................    2,016      564    1,598
                                                    --------  -------  -------
      Total adjustments............................   (7,821)     728     (103)
                                                    --------  -------  -------
      Net cash provided by (used in) operating
       activities..................................   17,333    6,731   (1,976)
                                                    --------  -------  -------
Cash flows from investing activities:
  Purchases of product licenses....................   (1,000)    (550)      (3)
  Capital expenditures.............................   (4,694)  (3,364)  (2,719)
  Purchase of other investment.....................   (2,499)     --       --
  Purchases of held to maturity investments........  (98,790)  (6,405)  (8,615)
  Proceeds from maturities of investments..........   45,688    4,562   16,282
                                                    --------  -------  -------
      Net cash provided by (used in) investing
       activities..................................  (61,295)  (5,757)   4,945
                                                    --------  -------  -------
Cash flows from financing activities:
  Payments on product license obligations..........     (303)  (1,045)    (727)
  Proceeds from the exercise of stock options and
   warrants........................................    7,105    3,881      699
  Proceeds from the issuance of common stock, net
   of issuance costs...............................   68,181      --       --
  Proceeds from the issuance of convertible
   preferred stock, net of issuance costs..........      --       (75)  13,656
                                                    --------  -------  -------
      Net cash provided by financing activities....   74,983    2,761   13,628
                                                    --------  -------  -------
Increase in cash and cash equivalents..............   31,021    3,735   16,597
Cash and cash equivalents at beginning of year.....   24,243   20,508    3,911
                                                    --------  -------  -------
Cash and cash equivalents at end of year........... $ 55,264  $24,243  $20,508
                                                    ========  =======  =======
Supplemental disclosure of cash flows information:
  Cash paid for interest........................... $     33  $   109  $   181
  Cash paid for income taxes....................... $    453  $   214  $    30
  Tax benefit realized from exercise of stock
   options......................................... $  8,266  $   --   $   --
</TABLE>

          See accompanying notes to consolidated financial statements.

                                      F-6
<PAGE>

                    TRANSWITCH CORPORATION AND SUBSIDIARIES

                  NOTES TO CONSOLIDATED FINANCIAL STATEMENTS

              (in thousands, except share and per share amounts)
                          December 31, 1999 and 1998

(1) Summary of Significant Accounting Policies

 Description of Business

   TranSwitch Corporation (the "Company") was incorporated in Delaware on
April 26, 1988. The Company has three wholly-owned subsidiaries: TranSwitch
Europe N.V./S.A. in Brussels, Belgium, TranSwitch India Private Limited in New
Delhi, India and TranSwitch S.A. in Lausanne, Switzerland. The Company
designs, develops, markets and supports highly integrated digital and mixed-
signal semiconductor solutions for the telecommunications and data
communications markets.

 Principles of Consolidation

   The consolidated financial statements include the accounts of the Company
and its wholly-owned subsidiaries. All intercompany accounts and transactions
have been eliminated in consolidation.

 Reclassifications

   Certain prior year amounts have been reclassified to conform with the
current year's presentation.

 Cash Equivalents

   Cash equivalents of $44,119 and $13,262 at December 31, 1999 and 1998,
respectively, consist of certificates of deposit, U.S. Treasury Bills,
commercial paper and U.S. Agency notes. For purposes of the statements of cash
flows, the Company considers all certificates of deposit, U.S. Treasury Bills,
commercial paper and U.S. Agency notes with original maturities of three
months or less to be cash equivalents.

 Investments

   The Company's investments comprise U.S. Treasury Bills, commercial paper,
and corporate debt securities. Investments with maturities of less than one
year are considered short-term. Long-term investments consist of the same mix
of securities with maturity dates greater than one year from the balance sheet
date. The Company classifies its securities as held-to-maturity. Held-to-
maturity securities are those securities in which the Company has the ability
and intent to hold the securities to maturity. These securities are recorded
at amortized cost.

 Fair Value of Financial Instruments

   The carrying amounts for cash and cash equivalents, short-term investments,
and accounts receivables, net, approximate fair value because of the short
maturities of these instruments.

 Inventories

   Inventories are carried at the lower of cost (on a first-in, first-out
basis) or estimated net realizable value.

 Property and Equipment

   Property and equipment are carried at cost less accumulated depreciation.
Depreciation of property and equipment is provided on the half-year convention
method based on the related assets' estimated useful lives,

                                      F-7
<PAGE>

                    TRANSWITCH CORPORATION AND SUBSIDIARIES

            NOTES TO CONSOLIDATED FINANCIAL STATEMENTS--(Continued)


ranging from three to seven years. Depreciation of semiconductor tooling costs
is provided on the straight-line method using the lesser of three years or the
estimated life of the related semiconductor it produces. Repairs and
maintenance are charged to operations as incurred.

 Product Licenses

   Product licenses are amortized over the lesser of the Company's estimated
product sales volume or the straight-line method over three to five years.
Amortization expense is included in cost of revenues.

   Subsequent to its acquisition, the Company continually evaluates whether
events and circumstances have occurred that indicate the remaining estimated
useful life of a product license may warrant revision or that the remaining
balance of a product license may not be recoverable. When factors indicate that
a product license should be evaluated for possible impairment, the Company uses
an estimate of the related product license's undiscounted future cash flows
over the remaining life of the asset in measuring whether the product license
is recoverable. Any impairment is measured against discounted cash flows.

 Revenue Recognition

   Sales of product are recognized upon shipment to distributors and original
equipment manufacturers. Sales to certain distributors are made under
distributor agreements which provide the distributor with certain price
protection and return and allowance rights. Revenues are reduced for estimated
price protection and returns based upon historical experience.

   Revenues from development contracts are derived from agreements with third
parties. These agreements provide for payments to the Company for the
development of new products and reimbursement for expenses incurred based on
the achievement of certain milestones. Revenues are recognized as the related
costs are incurred over the term of the agreement. The Company primarily
retains exclusive ownership of technology developed in connection with the
design of semiconductors. Technology developed in connection with customized
computer boards generally transfers to third parties.

 Concentration of Credit Risk

   The Company sells its products to customers in the United States and
overseas. Credit evaluations are done on all new customers and periodically
evaluated for existing customers. The Company establishes an allowance for
doubtful accounts based upon factors surrounding the credit risk of specific
customers, historical trends and other information.

 Product Warranties

   The Company provides for expected costs that may be incurred under its
product warranties. Estimated warranty costs are accrued as products are sold
and charged to cost of revenues.

 Research and Development Costs

   Research and development costs are expensed as incurred.

 Software Development Costs

   Software development costs, which are required to be capitalized pursuant to
Statement of Financial Accounting Standards (SFAS) No. 86, "Accounting for the
Costs of Computer Software to Be Sold, Leased, or Otherwise Marketed," have not
been material to the Company to date.

                                      F-8
<PAGE>

                    TRANSWITCH CORPORATION AND SUBSIDIARIES

            NOTES TO CONSOLIDATED FINANCIAL STATEMENTS--(Continued)


 Income Taxes

   Income taxes are accounted for under the asset and liability method.
Deferred tax assets and liabilities are recognized for the future tax
consequences attributable to differences between the financial statement
carrying amounts of existing assets and liabilities and their respective tax
bases, and operating loss and tax credit carryforwards. Deferred tax assets and
liabilities are measured using enacted tax rates expected to apply to taxable
income in the years in which those temporary differences are expected to be
recovered or settled. The effect on deferred tax assets and liabilities of a
change in enacted tax is recognized in income in the period that includes the
enactment date.

 Earnings per Share

   Basic earnings per share are based upon the weighted average common shares
outstanding during the period. Diluted earnings per share assume exercise of
stock options outstanding and full conversion of convertible preferred stock
into common stock at the beginning of the period or the date of issuance,
unless they are antidilutive.

   Share and per-share data reflect the three-for-two stock split effective
June 8, 1999 and the three-for-two stock split effective January 10, 2000. All
amounts have been retroactively restated for both stock splits.

 Foreign Currency Translation Adjustment

   All of the Company's international subsidiaries use their local currency as
their functional currency. Therefore, assets and liabilities are translated at
exchange rates in effect at the balance sheet date and income and expense
accounts at average exchange rates during the year. Resulting translation
adjustments have been immaterial.

 Use of Estimates

   Management of the Company has made a number of estimates and assumptions
relating to the reporting of assets and liabilities and the disclosure of
contingent liabilities to prepare these financial statements in conformity with
generally accepted accounting principles. Actual results could differ from
those estimates.

 Accounting Changes

   In June 1998, the Financial Accounting Standards Board issued SFAS No. 133,
"Accounting for Derivative Instruments and Hedging Activities." SFAS No. 133
requires companies to recognize all derivatives as assets or liabilities
measured at their fair value. Gains or losses resulting from changes in the
value of those derivatives would be accounted for depending on the use of the
derivative and whether it qualifies for hedge accounting. We will adopt SFAS
No. 133, as amended, beginning January 1, 2001. The Company has not yet made a
determination of the impact of this accounting standard on its financial
position or results of operations.

(2) Investments

   Long-term investments are carried at cost.

   Financial instruments that potentially subject the Company to significant
concentrations of credit risk consist principally of cash and trade accounts
receivable.

   The Company places its cash primarily in market interest rate accounts. The
Company, by policy, limits the amount of credit exposure to any one financial
institution or commercial issuer.

                                      F-9
<PAGE>

                    TRANSWITCH CORPORATION AND SUBSIDIARIES

            NOTES TO CONSOLIDATED FINANCIAL STATEMENTS--(Continued)


   The following table summarizes the Company's investment in securities at
December 31, 1999:

<TABLE>
<CAPTION>
                                                   Gross      Gross
                                       Amortized Unrealized Unrealized  Fair
                                         Cost      Gains     (Losses)   Value
                                       --------- ---------- ---------- -------
   <S>                                 <C>       <C>        <C>        <C>
   Money market & CD's................ $  5,561     $  6      $ --     $ 5,567
   U.S Gov. & agency obligations......   12,265      --         (74)    12,191
   Corporate bonds & commercial
    paper.............................   82,349      --        (255)    82,094
                                       --------     ----      -----    -------
       Total.......................... $100,175     $  6      $(330)   $99,851
                                       ========     ====      =====    =======
   Reported as :
     Cash Equivalents................. $ 44,119
     Short--term investments..........   20,053
     Long--term investments...........   36,003
                                       --------
       Total.......................... $100,175
                                       ========
</TABLE>

(3) Inventories

   The components of inventories at December 31, 1999 and 1998 follow:

<TABLE>
<CAPTION>
                                                                     1999  1998
                                                                    ------ -----
       <S>                                                          <C>    <C>
       Raw materials............................................... $1,017   947
       Work in process.............................................  1,121   809
       Finished goods..............................................  5,762 3,720
                                                                    ------ -----
         Total inventories......................................... $7,900 5,476
                                                                    ====== =====
</TABLE>

(4) Property and Equipment, Net

   The components of property and equipment, net, at December 31, 1999 and 1998
follow:

<TABLE>
<CAPTION>
                                                  Estimated
                                                    useful
                                                    lives      1999     1998
                                                  ---------- --------  ------
       <S>                                        <C>        <C>       <C>
       Purchased computer software............... 3 years    $  6,467   4,732
       Equipment................................. 3-7 years     7,439   5,383
       Semiconductor tooling..................... 3 years       1,077     998
       Furniture................................. 3-7 years     1,596   1,120
       Leasehold improvements.................... Lease term      563     196
       Construction in progress..................                 321     353
                                                             --------  ------
                                                               17,463  12,782
       Less accumulated depreciation and
        amortization.............................             (10,345) (7,639)
                                                             --------  ------
       Property and equipment, net...............            $  7,118   5,143
                                                             ========  ======
</TABLE>

(5) Product Licenses, Net

   From time to time, the Company will acquire the rights to certain technology
for use in the manufacture of new products. During 1999 and 1998, the Company
capitalized $1,000 and $550, respectively, in connection with the acquisition
of selected technologies.

                                      F-10
<PAGE>

                    TRANSWITCH CORPORATION AND SUBSIDIARIES

            NOTES TO CONSOLIDATED FINANCIAL STATEMENTS--(Continued)


   Product licenses, net, amounted to $1,657 and $1,142 at December 31, 1999
and 1998, respectively. Amortization of product licenses amounted to $485,
$408, and $257 in 1999, 1998 and 1997, respectively.

(6) Segment Reporting

   In 1998, the Company adopted SFAS No. 131, "Disclosures about Segments of
an Enterprise and Related Information." SFAS No. 131 establishes standards for
reporting information about operating segments in annual financial statements
and requires that certain selected information about operating segments be
reported in interim financial reports. It also establishes standards for
related disclosures about products and services, and geographic areas.
Operating segments are defined as components of an enterprise about which
separate financial information is evaluated regularly by the chief operating
decision maker, or decision making group, in deciding how to allocate
resources and in assessing performance. The Company's chief operating decision
maker is our Chief Executive Officer. SFAS No. 131 differs from the previous
accounting standard SFAS No. 14, which required companies to disclose certain
financial information about an industry segment in which they operate. Under
both SFAS No. 14 and SFAS No. 131, we have one segment: Communication
Semiconductor Products.

 Products and Services

   TranSwitch products are Very Large Scale Integrated (VLSI) semiconductor
solutions that provide core functionality for communications network
equipment. The integration of various technologies and standards in these
solutions result in a homogeneous product line for management and measurement
purposes.

 Information about Geographic Areas

   The following revenues from external customers is based on the geographic
location of the Company's customers. All product sales to foreign customers
are exported from the United States and are denominated in U.S. dollars.

<TABLE>
<CAPTION>
                                                           Years Ended December
                                                                    31,
                                                           ---------------------
                                                            1999    1998   1997
                                                           ------- ------ ------
   <S>                                                     <C>     <C>    <C>
   Revenues:
     United States.......................................  $49,763 23,689 18,059
     Israel..............................................    2,934  5,772    517
     China...............................................    2,358  7,175  1,831
     Other areas.........................................   16,352  7,533  6,677
                                                           ------- ------ ------
       Total revenues....................................  $71,407 44,169 27,084
                                                           ======= ====== ======

   Export revenues represented 30%, 46% and 33% of total revenues in 1999,
1998 and 1997, respectively.

   Long-lived assets of the Company are located in the following areas at
December 31, 1999, 1998, and 1997, respectively:

<CAPTION>
                                                               December 31,
                                                           ---------------------
                                                            1999    1998   1997
                                                           ------- ------ ------
   <S>                                                     <C>     <C>    <C>
   Long-lived assets:
     United States.......................................   $6,516  4,677  3,499
     Foreign countries...................................      502    466    317
                                                           ------- ------ ------
       Total long-lived assets...........................   $7,118  5,143  3,816
                                                           ======= ====== ======
</TABLE>

                                     F-11
<PAGE>

                    TRANSWITCH CORPORATION AND SUBSIDIARIES

            NOTES TO CONSOLIDATED FINANCIAL STATEMENTS--(Continued)


 Information about Major Customers

   The percentage of total revenues attributable to the Company's significant
customers for the years ended December 31, 1999, 1998 and 1997 follow:

<TABLE>
<CAPTION>
                              Years Ended December 31,
                             ------------------------------
                               1999       1998       1997
                             --------   --------   --------
   <S>                       <C>        <C>        <C>
   Insight Electronics,
    Inc.(1)................        34%        20%        41%
   Columbia
    Technologies(1)........         *         15%         *
   Tellabs Operations,
    Inc.(2)................        13%        21%        16%
   Lucent Technologies(3)..        16%         *          *
   Northern Telecom(3).....        13%         *          *
</TABLE>
--------
(1)  Insight Electronics, Inc. and Columbia Technologies are distributors to
     various end-users, none of which comprised more than 10% of the Company's
     total revenue during the respective periods.
(2)  The Company's sales to Tellabs Operations, Inc. during 1999 were made
     through Arrow Electronics, Inc., Tellabs' designated distributor. In 1998,
     sales to Tellabs were made through Reptron Electronics, Inc. and Arrow
     Electronics, Inc., which are Tellabs' designated distributors. In 1997 and
     1996, sales to Tellabs were made through Reptron Electronics, Inc. only.
     The remaining end users to which Arrow sells do not compromise more than
     10% of the Company's end users.
(3)  The Company's sales to Lucent Technologies and Northern Telecom consist of
     direct sales and sales through third party distributors.
 *  Revenues were less than 10% of the Company's total revenues in these years.

(7) Income Taxes

   The components of 1999 and 1998 income before income taxes are as follows:

<TABLE>
<CAPTION>
                                                                  Years Ended
                                                                  December 31,
                                                                 --------------
                                                                  1999    1998
                                                                 ------- ------
   <S>                                                           <C>     <C>
   Domestic income.............................................. $22,174 $6,212
   Foreign income...............................................      88     75
                                                                 ------- ------
   Income before income taxes................................... $22,262 $6,287
                                                                 ======= ======
</TABLE>

   The provision (benefit) for income taxes is comprised of the following:

<TABLE>
<CAPTION>
                                                     Years Ended December 31,
                                                    -----------------------------
                                                       1999      1998     1997
                                                    ----------  -------- --------
   <S>                                              <C>         <C>      <C>
   Federal income taxes
     Current....................................... $    1,581      161     --
     Deferred......................................     (4,682)    (161)    --
   State income taxes
     Current.......................................        434      252     --
     Deferred......................................       (263)     --      --
   Foreign income taxes
     Current.......................................         38       32     --
     Deferred......................................        --       --      --
                                                    ----------  -------  ------
   Income taxes.................................... $   (2,892)     284     --
                                                    ==========  =======  ======
</TABLE>

                                      F-12
<PAGE>

                    TRANSWITCH CORPORATION AND SUBSIDIARIES

            NOTES TO CONSOLIDATED FINANCIAL STATEMENTS--(Continued)


   The following table summarizes the differences between the U.S. Federal
statutory rate and the Company's effective tax rate for financial statement
purposes for the years ended December 31, 1999 and 1998:

<TABLE>
<CAPTION>
                                                              Years Ended
                                                              December 31,
                                                            ------------------
                                                              1999      1998
                                                            --------   -------
   <S>                                                      <C>        <C>
   U.S federal statutory tax rate..........................     35.0 %    34.0 %
   State taxes.............................................      0.8       4.0
   Utilization of NOL......................................      --      (34.4)
   Change in valuation allowance...........................    (48.2)
   Permanent differences and other.........................     (0.6)      0.9
                                                            --------   -------
   Effective income tax rate...............................    (13.0)%     4.5%
                                                            ========   =======

   The tax effect of temporary differences that give rise to deferred tax
assets and deferred tax liabilities at December 31, 1999 and 1998 are presented
below:

<CAPTION>
                                                              Years Ended
                                                              December 31,
                                                            ------------------
                                                              1999      1998
                                                            --------   -------
   <S>                                                      <C>        <C>
   Deferred tax assets:
     Property and equipment................................ $    295       160
     Nondeductible reserves................................    2,332     1,710
     Net operating losses..................................    9,215    10,333
     Research and development credit.......................    2,599     2,429
     Other.................................................      354       366
                                                            --------   -------
   Total gross deferred tax assets.........................   14,795    14,998
   Less: valuation allowance...............................     (833)  (14,825)
                                                            --------   -------
   Net deferred tax assets.................................   13,963       173
                                                            --------   -------
   Deferred tax liability--product license.................      (62)     (125)
                                                            --------   -------
   Total deferred taxes, net of valuation allowance........ $ 13,901        48
                                                            ========   =======
</TABLE>

   The net change in the total valuation allowance for the year ended December
31, 1999 was a net decrease of approximately $14,000. During 1999, the Company
concluded that it is more likely than not that substantially all of its net
deferred tax assets will be realized due to the Company's continuing
profitability and forecasts of taxable income. Of the $14,000 valuation
allowance reversal, approximately $12,000 was recorded as a tax benefit in the
statement of operations, and approximately $2,000 as an increase in additional
paid in capital, which represents the amount of deferred tax assets generated
from the exercise of stock options. Of the remaining valuation allowance of
$833, subsequently recognized tax benefits, if any, in the amount of $833 will
be applied directly to contributed capital. This amount relates to the tax
effect of employee stock option deductions included in the Company's net
operating loss ("NOL") carryforward. The deferred tax asset is recorded as both
current and non-current in the amounts of $2,334 and $11,567, respectively. The
current portion is recorded in other assets.

   At December 31, 1999, the Company had available, for federal income tax
purposes, net operating loss (NOL) carryforwards of approximately $23,948 and
research and development tax credit carryforwards of approximately $2,599
expiring in varying amounts from 2003 through 2019.

                                      F-13
<PAGE>

                    TRANSWITCH CORPORATION AND SUBSIDIARIES

            NOTES TO CONSOLIDATED FINANCIAL STATEMENTS--(Continued)


   Certain transactions involving beneficial ownership of the Company have
occurred which resulted in a stock ownership change for purposes of Section 382
of the Internal Revenue Code of 1986, as amended. Consequently, approximately
$21,852 of the Company's NOL carryforward and $1,410 of the Company's research
and development tax credit carryforward are subject to these limitations.
However, management believes it is more likely than not that the NOL and
research and development tax credits will be utilized.

(8)Stockholders' Equity

 Convertible Preferred Stock

   On October 10, 1997, the Company issued 14,500 shares of Series A
Convertible Preferred Stock (Series A Stock) for net proceeds, after issuance
costs, of $13,656. The Company allocated $1,614 of the net proceeds to
additional paid-in capital, representing the calculated value of a preferential
conversion feature on the date of issuance. This amount was accreted ratably to
the Series A Stock as a deemed dividend through the earliest conversion date.

   Each share of Series A Stock is convertible into shares of Common Stock at
any time at the option of the holder, subject to certain limitations, at the
lesser of (i) $10.58 per share or (ii) ninety percent (90%) of the average of
the closing bid price of the Company's Common Stock, as reported by the NASDAQ
National Market, for the ten (10) trading days immediately preceding the date
written notice of conversion is received by the Company. Unless converted
sooner at the option of the holders of the Series A Stock, all shares of Series
A Stock will convert to Common Stock on October 10, 2002. No Series A Stock may
be converted until the earlier of (i) January 8, 1998 or (ii) the date upon
which a registration statement filed with the Securities and Exchange
Commission to register additional common shares is declared effective.

   As of December 31, 1997, the Series A Stock was not yet eligible for
conversion into Common Stock. Effective January 8, 1998, the Series A Stock was
eligible for conversion into Common Stock.

   As of December 31, 1998, all outstanding shares of Series A Stock had been
converted into 3,552,199 shares of Common Stock.

 Common Stock

   On February 9, 1999, the Company completed a follow-on public offering of
4,398,750 shares of Common Stock for net proceeds, after issuance costs, of
$68,181.

   As previously stated, the Company announced a 3-for-2 stock split which
became effective June 8, 1999, as well as a second three-for-two stock split
which became effective January 10, 2000. All share and per share amounts
reflect both stock splits retroactively.

   The Company, in connection with its May 1999 annual shareholders meeting,
received shareholder approval to increase its authorized shares to 100,000,000.

 Stock Based Compensation

 1995 Employee Stock Purchase Plan

   On April 11, 1995, the Company's Board of Directors adopted the 1995
Employee Stock Purchase Plan (the "1995 Purchase Plan") which was approved by
the Company's stockholders on April 19, 1995. Under the terms of the 1995
Purchase Plan, all employees of the Company except employees who own five
percent or more of Common Stock, may contribute to the plan, up to 5% of their
annual compensation toward the

                                      F-14
<PAGE>

                    TRANSWITCH CORPORATION AND SUBSIDIARIES

            NOTES TO CONSOLIDATED FINANCIAL STATEMENTS--(Continued)

purchase of the Company's Common Stock. The Company has reserved 150,000 shares
for issuance under the 1995 Purchase Plan. The purchase price per share is the
lesser of (a) 85% of the fair market value of the Common Stock on the date of
the grant of the option, as defined, or (b) 85% of the fair market value of the
Common Stock on the date of exercise of the option, as defined.

 Third Amended and Restated 1995 Stock Plan

   The Third Amended and Restated 1995 Stock Plan (the "Stock Plan") was
adopted by the Board of Directors on May 27, 1998. The Stock Plan currently
provides for the issuance of a maximum of 7,800,000 shares of the Company's
Common Stock pursuant to the grant to employees of incentive stock options and
the grant of non-qualified stock options, stock awards or opportunities to make
direct purchases of the Company's Common Stock to employees, consultants,
directors and executive officers of the Company. The terms of the options
granted will be subject to the provisions of the Stock Plan as determined by
the Compensation Committee of the Board of Directors. The Stock Plan will
terminate ten years after its adoption unless earlier terminated by the Board
of Directors.

   As of December 31, 1999 and 1998, 2,321,714 and 729,900 shares,
respectively, were available for grant under the Stock Plan.

 1995 Non-Employee Director Stock Option Plan

   The 1995 Non-Employee Director Stock Option Plan (the "Director Plan") was
adopted by the Board of Directors on April 11, 1995 and approved by the
Company's stockholders on April 19, 1995. The Director Plan provides for the
automatic grant of options to purchase shares of Common Stock, up to an
aggregate of 525,000 shares, to non-employee directors of the Company on the
anniversary date of each individual board member joining the Board of
Directors. Upon joining the Company's Board, Directors are granted an option to
purchase 18,750 shares, one-third of which vest immediately, one-third after
the first year, and the remaining one-third after the second year. Annually
thereafter, Directors are granted an option to purchase 14,400 shares which
vest fully after one year.

   The Director Plan is administered by the Compensation Committee of the Board
of Directors. No option granted under the Director Plan may be exercised after
the expiration of five years from the date of grant. The exercise price of
options under the Director Plan must be equal to the fair market value of the
Common Stock on the date of grant. Options granted under the Director Plan are
generally nontransferable.

                                      F-15
<PAGE>

                    TRANSWITCH CORPORATION AND SUBSIDIARIES

            NOTES TO CONSOLIDATED FINANCIAL STATEMENTS--(Continued)


 Stock Option Information

   Information regarding the Company's stock options is set forth as follows:

<TABLE>
<CAPTION>
                                                    Number of   Weighted average
                                                     options      option price
                                                    ----------  ----------------
   <S>                                              <C>         <C>
   Outstanding at December 31, 1996................  4,052,955      $  2.14
     Granted.......................................  3,012,300         3.23
     Exercised.....................................   (855,405)        0.66
     Canceled...................................... (1,326,639)        3.72
                                                    ----------      -------
   Outstanding at December 31, 1997................  4,883,211         2.54
     Granted.......................................  3,625,343         6.21
     Exercised..................................... (1,707,444)        2.17
     Canceled......................................   (346,395)        3.49
                                                    ----------      -------
   Outstanding at December 31, 1998................  6,454,715         5.29
     Granted.......................................  2,735,058        23.07
     Exercised..................................... (1,821,974)        3.65
     Canceled......................................   (457,763)        9.08
                                                    ----------      -------
   Outstanding at December 31, 1999................  6,910,036      $ 17.52
                                                    ==========      =======
</TABLE>

   Options outstanding and exercisable at December 31, 1999 are as follows:

<TABLE>
<CAPTION>
                                  Options outstanding                   Options exercisable
                     ---------------------------------------------- ----------------------------
                                     Weighted
    Range of           Number    Average remaining Weighted average   Number    Weighted average
 exercise prices     outstanding Contractual life   exercise price  Exercisable  exercise price
-------------------  ----------- ----------------- ---------------- ----------- ----------------
<S>     <C>  <C>     <C>         <C>               <C>              <C>         <C>
$ 0.53   to    3.83   1,189,989        6.60             $ 2.56         534,561       $ 2.51
  4.06   to    5.31   1,264,580        7.81               4.60         361,118         4.55
  5.61   to    8.47   1,549,292        8.60               6.56         293,857         6.63
  8.78   to   17.31     862,650        8.99              15.00          57,474        14.72
 17.39   to   20.22   1,077,450        6.97              18.82             --           --
 21.06   to   29.33     308,775        8.01              24.95           6,250        21.06
 30.00   to   32.67     394,500        6.77              31.53           4,000        30.00
 32.69   to   42.02     262,800        6.27              36.16             --           --
------       ------   ---------        ----             ------       ---------       ------
$ 0.53   to   42.02   6,910,036        7.50             $17.52       1,257,260       $13.25
======       ======   =========        ====             ======       =========       ======
</TABLE>

   Stock options expire five or ten years from the date of grant and are
generally exercisable ratably over four years from the date of grant.

   In connection with stock options granted in January 1995 through March 31,
1995, the Company recorded deferred compensation expense of $618 for the excess
of the deemed value for accounting purposes of the Common Stock issuable upon
exercise of such stock options over the aggregate exercise price of such
options. The Company is recording compensation expense over the applicable
vesting periods (primarily four years). For the years ended December 31, 1999,
1998 and 1997, the Company recorded compensation expense of $77, $155, and
$155, respectively, for these options. The value of the deferred compensation
is fully amortized as of December 31, 1999.

                                      F-16
<PAGE>

                    TRANSWITCH CORPORATION AND SUBSIDIARIES

            NOTES TO CONSOLIDATED FINANCIAL STATEMENTS--(Continued)


   The Company does not recognize compensation expense relating to employee
stock options because the exercise price of the option equals the fair value of
the Company's Common Stock on the date of grant. If the Company had determined
the compensation based on the fair value of the options on the date of grant in
accordance with SFAS No. 123, the pro forma net income (loss) and earnings
(loss) per share would be as follows:

<TABLE>
<CAPTION>
                                                         Years Ended December
                                                                 31,
                                                        ----------------------
                                                         1999    1998   1997
                                                        ------- ------ -------
   <S>                                                  <C>     <C>    <C>
   Net income (loss)--as reported...................... $25,154 $6,003 $(1,873)
   Net income (loss)--pro forma........................  12,849    590  (4,317)
   Basic earnings (loss) per share--as reported........    0.66   0.19   (0.07)
   Basic earnings (loss) per share--pro forma..........    0.34   0.04   (0.15)
   Diluted earnings (loss) per share--as reported......    0.62   0.18   (0.07)
   Diluted earnings (loss) per share--pro forma........    0.32   0.03   (0.15)
</TABLE>

   The effects of applying SFAS No. 123 in this pro forma disclosure are not
necessarily indicative of future amounts because it does not take into
consideration pro forma compensation expense related to grants made prior to
1995.

   As reflected in the pro forma amounts in the preceding table, the average
fair value of each option granted in 1999, 1998 and 1997 was $12.31, $7.64, and
$3.76, respectively. The fair value of each option granted was estimated on the
date of grant using the modified Black-Scholes option pricing model based on
the following weighted average assumptions:

<TABLE>
<CAPTION>
                                                               1999  1998  1997
                                                               ----  ----  ----
   <S>                                                         <C>   <C>   <C>
   Risk-free interest rate....................................  6.7%  5.2%  5.7%
   Expected life in years.....................................  7.2   8.1   7.7
   Expected volatility........................................ 73.0% 68.9% 66.0%
   Expected dividend yield....................................  --    --    --
</TABLE>

   For the years ended December 31, 1999, 1998 and 1997, the Company recognized
additional compensation expense of $56, $229 and $225 respectively, as required
by SFAS No. 123, relating to stock options granted to non-employees.

 Warrants

   Warrants to purchase Common Stock were granted to the original investors in
consideration of additional financing and loans, and for services performed by
various other parties. The warrants presented in the table below are
convertible into Common Stock at a rate of one share of Common Stock for each
warrant to purchase Common Stock.

<TABLE>
<CAPTION>
                                                     Warrants--Common Stock
                                                 -------------------------------
                                                 Number of Price per Expiration
                                                 warrants    share      date
                                                 --------- --------- -----------
   <S>                                           <C>       <C>       <C>
   Outstanding at December 31, 1996.............  10,434   $.40-1.00 12/96-11/98
     Exercised..................................  (8,038)        --  12/96-11/98
                                                  ------   --------- -----------
   Outstanding at December 31, 1997.............   2,396    .40-1.00 12/96-11/98
     Expired....................................  (2,396)        --          --
                                                  ------   --------- -----------
   Outstanding at December 31, 1998.............     --    $     --          --
                                                  ======   ========= ===========
</TABLE>


                                      F-17
<PAGE>

                    TRANSWITCH CORPORATION AND SUBSIDIARIES

            NOTES TO CONSOLIDATED FINANCIAL STATEMENTS--(Continued)

   The Company did not issue any warrants during the year ended December 31,
1999.

(9) Earnings Per Share

   The basic earnings (loss) per share for the years ended December 31, 1999,
1998 and 1997 follows:

<TABLE>
<CAPTION>
                                                          Years Ended December
                                                                   31,
                                                          ---------------------
                                                           1999    1998   1997
                                                          ------- ------ ------
   <S>                                                    <C>     <C>    <C>
   Net income (loss)..................................... $25,154  6,003 (1,873)
   Average shares (in thousands).........................  38,085 31,334 27,342
   Basic earnings (loss) per share....................... $  0.66   0.19  (0.07)
</TABLE>

   Diluted earnings per share for the years ended December 31, 1999 and 1998
follows:

<TABLE>
<CAPTION>
                                                                 Years Ended
                                                                December 31,
                                                               ---------------
                                                                1999    1998
                                                               ------- -------
   <S>                                                         <C>     <C>
   Net income................................................. $25,154 $ 6,003
                                                               ======= =======
   Average common shares outstanding for the period (in
    thousands)................................................  38,085  31,334
   Stock options, net of assumed treasury share repurchases
    (in thousands)............................................   2,460   2,154
                                                               ------- -------
   Adjusted average shares outstanding for the period (in
    thousands)................................................  40,545  33,488
                                                               ======= =======
   Diluted earnings per share................................. $  0.62 $  0.18
                                                               ======= =======
</TABLE>

   Diluted loss per share amount is not presented for the year ended December
31, 1997 as it is the same as basic. Because the Company recorded a net loss in
this year, the assumed exercise of dilutive securities would be antidilutive.

   The weighted average shares of dilutive securities that would have been used
to calculate diluted EPS had their effect not been anti-dilutive for the year
ended December 31, 1997 are as follows:

<TABLE>
   <S>                                                                 <C>
   Stock options...................................................... 1,428,452
   Warrants...........................................................     4,397
   Convertible preferred stock........................................   856,569
                                                                       ---------
     Total............................................................ 2,289,418
                                                                       =========
</TABLE>

(10) Employee Savings Plan

   On November 21, 1988, the Company established a 401(k) retirement savings
plan (the "Plan"). All employees are entitled to contribute from 1% to 15% of
their pre-tax income to the Plan, not to exceed the IRS maximum for income
deferrals. Each participant may elect to invest their contributions in various
established funds, which include money market, fixed income and equity funds.
In 1999, the maximum contribution was 20% of pre-tax income subject to IRS
limitations. In 1996, the Company began providing matching contributions equal
to 50% of the employees' deferred compensation, up to a maximum of 6% . The
Company's contribution expense amounted to $307, $230 and $188 for 1999, 1998
and 1997, respectively.

                                      F-18
<PAGE>

                    TRANSWITCH CORPORATION AND SUBSIDIARIES

            NOTES TO CONSOLIDATED FINANCIAL STATEMENTS--(Continued)


(11) Commitments and Contingencies

 Line of Credit

   In July 1999, the Company extended the time frame of its line of credit
agreement with Silicon Valley Bank which allows the Company access up to $8,000
for working capital purposes, bearing interest at prime +3/4% due on July 8,
2000, and $2,000 for equipment purchases, bearing interest at prime +1% due on
May 31, 2002. The line is unsecured. The Company has a pledge that it will seek
Silicon Valley Bank approval prior to allowing another party to secure the
Company's assets.

   The agreement contains certain financial restrictions and covenants which,
among other things, include provisions for maintaining a minimum amount of
cash, net worth and profitability.

   At December 31, 1999 and 1998, no amounts were outstanding under this
agreement.

 Development Agreements

   From time to time, the Company has entered into agreements with third
parties for the development and/or licensing of products for its manufacture
and sale, or the licensing of technology that the Company may use in the
manufacture of products, for which royalties are paid based upon actual sales
of these products. The Company recognized royalty expense of $680, $673 and
$829 in 1999, 1998 and 1997, respectively, under these agreements. These
amounts are included in cost of revenues in the consolidated statements of
operations.

 Lease Agreements

   Total rental expense under all operating lease agreements aggregated $1,113,
$797 and $745 during 1999, 1998 and 1997, respectively. Future minimum
operating lease commitments that have remaining, non-cancelable lease terms in
excess of one year at December 31, 1999 follow:

<TABLE>
   <S>                                                                    <C>
   2000.................................................................. $  784
   2001..................................................................    631
   2002..................................................................    595
   2003..................................................................    597
   2004..................................................................    584
   Thereafter............................................................  1,488
                                                                          ------
                                                                          $4,679
                                                                          ======
</TABLE>

(12) Subsequent Events

 3-for-2 Stock Split

   On January 10, 2000, the Company issued Common Stock under a stock split
declared in December 1999 for holders of record on December 29, 1999. This
stock split has been reflected in the per share and outstanding common share
amounts.

                                      F-19