United States Court of Appeals 

for the Federal Circuit 

__________________________ 

TELCORDIA TECHNOLOGIES, INC., 

Plaintiff-Appellant, 

v. 

CISCO SYSTEMS, INC., 

Defendant-Cross Appellant. 

__________________________ 

2009-1175, -1184 

__________________________ 

Appeals from the United States District Court for the 

District of Delaware in case no. 04-CV-876, Chief 

Judge Gregory M. Sleet. 

___________________________ 

Decided: July 6, 2010 

___________________________ 

DONALD R. DUNNER, Finnegan, Henderson, Farabow, 

Garrett & Dunner, L.L.P., of Washington, DC, argued for 

plaintiff-appellant. With him on the brief were DON O.

BURLEY, DARREL C. KARL, and JOHN M. WILLIAMSON. 

EDWARD R. REINES, Weil, Gotshal & Manges LLP, of 

Redwood Shores, California, argued for defendant-cross 

appellant. With him on the brief was SONAL N. MEHTA. 

__________________________ 
TELCORDIA TECH v. CISCO SYSTEMS 2

Before RADER*, Chief Judge, LOURIE and PROST, Circuit 

Judges. 

Opinion for the court filed by Chief Judge RADER. Opinion dissenting in part filed by Circuit Judge PROST. 

RADER, Chief Judge. 

Telcordia Technologies, Inc. (“Telcordia”) initiated this 

suit against Cisco Systems, Inc. (“Cisco”) alleging infringement of U.S. Patent Nos. 4,893,306 (“’306 patent”); 

4,835,763 (“’763 patent”); and RE 36,633 (“’633 patent”). 

The United States District Court for the District of Delaware granted summary judgment of non-infringement of 

the ’306 patent. Telcordia Techs., Inc. v. Cisco Sys., Inc., 

514 F. Supp. 2d 598, 603-07 (D. Del. 2007). At trial, the 

jury found that Cisco willfully infringed the ’763 and ’633 

patents and upheld the validity of all three asserted 

patents. The jury awarded $6.5 million in damages. 

Following trial, the district court denied Cisco’s motion for 

judgment as a matter of law (“JMOL”) that the ’306 

patent was anticipated and that the ’763 patent was 

invalid as indefinite. Telcordia Techs., Inc. v. Cisco Sys., 

Inc., 592 F. Supp. 2d 727, 738-40, 743-44 (D. Del. 2009). 

The district court awarded prejudgment interest on the 

$6.5 million damages award. Id. at 748-50. Further, the 

district court awarded an accounting for interim sales 

from January 31, 2007 to the date of the judgment. Id. at 

748-50. In addition, the district court ordered the parties 

to negotiate the terms of a royalty that would apply to the 

accounting and to post-judgment sales. Id. 

On appeal, Telcordia challenges the district court’s 

claim construction with respect to the ’306 patent. Cisco 

cross-appeals the district court’s holding that the asserted 

 * Randall R. Rader assumed the position of Chief 

Judge on June 1, 2010. 
3 TELCORDIA TECH v. CISCO SYSTEMS

claims of the ’306 and ’763 patents are not invalid. Cisco 

also contests the district court’s award of an accounting 

and pre-judgment interest, and its order requiring the 

parties to negotiate the royalty. 

Because the district court erroneously construed the 

only term on which it based its denial of Cisco’s JMOL 

motion on invalidity of the ’306 patent, this court vacates 

that decision and remands for determination of the validity issue. This court also remands to provide the parties 

an opportunity to negotiate the terms of the royalty. In 

all other respects, this court affirms. 

I. 

Telcordia owns by assignment the ’306 patent, the 

’763 patent, and the ’633 patent. The patents relate to 

transmission of data in telecommunications networks. 

The ’306 patent—“Method and Apparatus for Multiplexing Circuit and Packet Traffic”—issued on January 9, 

1990, based on a November 10, 1987 application. The 

’763 patent—“Survivable Ring Network”—issued on May 

30, 1989, based on a February 4, 1988 application. The 

’633 patent—”Synchronous Residual Time Stamp for 

Timing Recovery in a Broadband Network”—issued on 

March 28, 2000, as a reissue of U.S. Patent No. 5,260,978. 

A. 

The ’306 patent describes a data transmission technique called Dynamic Time Division Multiplexing 

(“DTDM”). DTDM is compatible with both the circuit 

transmission format and the packet transmission format. 

In the late 1980’s, the public telephone network began 

shifting from the circuit transmission format to the packet 

transmission format. The “commonly-held view as to how 

to introduce packet technology into the public network 

[was] to deploy a packet overlay network.” ’306 patent 
TELCORDIA TECH v. CISCO SYSTEMS 4

col.3 ll.3-18. This migration strategy required building a 

packet transmission network on top of a circuit transmission network. The patented invention aimed to provide 

an alternate migration strategy between the two different 

transmission formats. 

A system implementing DTDM allocates discrete 

segments, or “frames,” of a single transmission line to 

several sources (e.g., voice, video, and data). A frame is 

the basic unit of transmission: 

Id. at fig.1. Each frame has two fixed-length fields: a 

transmission overhead (“T”) and a payload. The transmission overhead has, for example, frame timing information and the empty/full status of the frame. The payload 

field has a header field (“H”) for storing the sender’s and 

recipient’s addresses, and an information field for storing 

the actual data for transmission. Rather than pre-assign 

the frames to each information source, the DTDM system 

dynamically allocates the frames to each source based on 

the source’s priority level and data availability. 

Figure 2 illustrates how a multiplexer called a 

“DTDM Assembler” (3) merges traffic from three different 

information sources (5, 7, 9) into a single DTDM bit 

stream (12). 
5 TELCORDIA TECH v. CISCO SYSTEMS

Id. at fig.2. The system generates a train of DTDM 

frames (10) with occupied transmission overhead fields 

and empty payload fields. Id. at col.4 l.65-col.5 l.2. This 

train has “a bit rate which defines a basic backbone 

transmission rate” for the system. Id. at col.5 ll.2-4. The 

information sources transmit, for example, voice (5), video 

(7), and data (9), over their data lines or “tributaries.” 

The incoming data segments may be in the circuit transmission format or the packet transmission format. Packetizers (11, 13, 15) put the incoming data segment into a 

packet structure by adding a packet header (“H”) at the 

beginning of each data segment. The DTDM assembler 

inserts the packets into the empty payload fields of the 

DTDM frames. If the DTDM assembler simultaneously 

receives packets from multiple information sources, the 

DTDM assembler selects the packet with the highest 

priority level. The resulting DTDM bit stream (12) contains packets from multiple information sources.

Telcordia alleges that Cisco infringes claims 1, 3, and 

4 of the ’306 patent. Claims 1 and 3 are method claims. 

Claim 4 is an apparatus claim. Each is stated below 

(important phrases underlined): 
TELCORDIA TECH v. CISCO SYSTEMS 6

1. A method for simultaneously transmitting data 

from sources having different bit rates in a telecommunication network comprising the steps of: 

generating a bit stream comprising a sequence of 

frames, each of said frames including a transmission overhead field containing frame timing information and an empty payload field, and 

filling the empty payload fields in said frames 

with data in packetized format from a plurality of 

sources which have access to the bit stream including circuit or packet sources, such that data in 

packetized format from any of said sources is written into any available empty payload field of any 

of said frames for transmitting data from each of 

said sources at its own desired bit rate via said bit 

stream and for transmitting data from said plurality of sources simultaneously via said bit 

stream. 

Id. at col.17 ll.44-61 (emphases added). 

3. A method for generating a bit stream capable of 

transporting data originating from both circuit 

transmission and packet sources comprising 

generating a bit stream comprising a sequence of 

frames, each of said frames including a transmission overhead field containing frame timing information and an empty payload field, 

packetizing data from a plurality of sources having different bit rates and which have access to 

said bit stream including circuit transmission 

sources or customer premises equipment to produce data packets, and 
7 TELCORDIA TECH v. CISCO SYSTEMS

inserting said packets from said sources into the 

empty payload fields of said frames such that a 

packet from any of said sources is inserted into any 

available empty payload field of any of said 

frames for transmitting data from each of said 

sources at its own desired bit rate via said bit 

stream and for transmitting data from said plurality of sources simultaneously using said bit 

stream. 

Id. at col.18 ll.1-20 (emphases added). 

4. An apparatus for assembling a dynamic time 

division multiplexing bit stream comprising, 

generating means for generating a train of frames 

wherein each frame includes a transmission overhead field containing timing information and an 

empty payload field, 

processing means for processing data from a plurality of sources into packet format, and 

inserting means for receiving said train of frames 

and for inserting each of said packets comprised of 

data from one of said plurality of sources into any 

empty payload field of any of said frames available 

to said inserting means to form said bit stream so 

that data from each of said sources can be transmitted at its own desired bit rate via said bit 

stream and so that data from said plurality of 

sources can be transmitted simultaneously via 

said bit stream. 

Id. at col.18 ll.21-37 (emphases added). 
TELCORDIA TECH v. CISCO SYSTEMS 8

B. 

The ’763 patent claims a survivable or self-healing 

ring network that can withstand a cut line or failed node. 

Figure 2 illustrates the invention: 

’763 patent fig.2. 

The invention consists of two rings carrying identical 

multiplexed node-to-node communications in opposite 

directions. A node (1), for example, has controllers (117, 

118) and selectors (119-121). Each node can detect a 

break (122) in either ring by monitoring the arriving 

signals for defects. If an arriving signal is defective, the 

controller in the node inserts an error signal on the specific channels that were lost due to the break. When 
9 TELCORDIA TECH v. CISCO SYSTEMS

these error-containing channels reach their destination 

node, the selector in the node will detect the error signal 

and select the identical, error-free channels from the 

other ring. 

Monitoring of errors in the arriving signals is essential to the invention. The asserted independent claims 1 

and 7 both claim this functionality via the “monitoring 

means” requirement. Claim 1 is illustrative (important 

phrase underlined): 

1. In a communications network having a plurality of nodes interconnected in a ring configuration 

by a first ring which conveys multiplexed subrate 

communications around the first ring from node to 

node in one direction and a second ring which 

conveys multiplexed subrate communications 

around the second ring from node to node in the 

other direction, each node including subrate 

transmitters with associated multiplexers and 

demultiplexers with associated subrate receivers, 

an improved node comprising 

monitoring means, associated with the first ring 

and the second ring, for evaluating the integrity of 

the multiplexed subrate communications on the 

first ring and the second ring, respectively, and 

insertion means, associated with the demultiplexers and said monitoring means, for inserting an 

error signal on designated ones of the subrate 

communications in response to said monitoring 

means detecting a lack of integrity on the multiplexed subrate communications on the first ring 

or the second ring or both the first ring and the 

second ring. 

Id. at col.4 l.53-col.5 l.5 (emphasis added). 
TELCORDIA TECH v. CISCO SYSTEMS 10

C. 

The accused products are Cisco routers and switches 

that transmit asynchronous transfer mode (“ATM”) cells 

and other types of packets over synchronous optical 

network (“SONET”). SONET is an industry standard for 

optical transmission. ATM is a protocol for dividing data 

from multiple sources into small segments called “cells” 

and intermixing those cells for transmission across a 

network. The accused routers and switches purportedly 

have SONET framers that multiplex the ATM cells into a 

frame called a Synchronous Transport Signal One. 

D. 

Telcordia sued Cisco for infringement of the ’306, ’633, 

and ’763 patents. On June 22, 2006, the district court 

issued a claim construction order. Telcordia conceded 

that it could not establish infringement of the ’306 patent 

based on the district court’s claim construction. Specifically, Telcordia could not prove that the accused Cisco 

products met the following limitations: (1) the “empty 

payload fields” limitations of claims 1, 3, and 4; and (2) 

the “having access” limitations of claims 1 and 3. The 

district court, however, denied Telcordia’s Rule 54(b) 

motion to have a judgment of non-infringement of the ’306 

patent entered against it. 

Cisco then moved for a summary judgment of noninfringement of the ’306 patent. Cisco argued that the 

accused products lacked not only the two claim limitations that Telcordia had conceded were missing but four 

additional claim limitations. The district court granted 

Cisco’s motion “on all grounds raised by [Cisco].” Telcordia, 514 F. Supp. 2d at 603-07. 

In April to May 2007, the district court held a trial on 

infringement of the ’633 and ’763 patents and validity of 
11 TELCORDIA TECH v. CISCO SYSTEMS

all three patents. On May 10, 2007, the jury returned a 

unanimous verdict for Telcordia on all claims. The jury 

found that Cisco willfully infringed all asserted claims of 

the ’633 and ’763 patents. The jury also upheld the validity of the ’306, ’633, and ’763 patents. On May 16, 2007, 

the district court entered a judgment on the verdict. 

On January 6, 2009, the district court granted Telcordia’s motion for an award of prejudgment interest and an 

accounting of Cisco’s infringing sales from January 31, 

2007 to the date of the judgment. Telcordia, 592 F. Supp. 

2d at 748-50. The district court ordered the parties to 

negotiate the terms of the royalty. Id. The district court 

denied Cisco’s JMOL motion that the asserted claims of 

the ’306 patent claims are invalid as anticipated. Id. at 

743-44. The district court also denied Cisco’s JMOL 

motion that the asserted claims of the ’763 patent are 

invalid as indefinite. Id. at 738-40.

On appeal, Telcordia challenges the district court’s 

claim construction and summary judgment of noninfringement of the ’306 patent. Cisco cross-appeals the 

district court’s denial of its JMOL motions on validity of 

the ’306 and ’763 patents. Cisco also appeals the district 

court’s damages awards. This court has jurisdiction 

under 28 U.S.C. § 1295(a)(1). 

III. 

Telcordia challenges the district court’s construction 

of six terms in the ’306 patent, all of which formed independent grounds for the district court’s summary judgment of non-infringement. This court first construes the 

term “empty payload field” in claims 1, 3, and 4, as the 

definition affects other construed terms. Because this 

court agrees with the district court’s construction of the 

term “such that . . . [a packet is inserted into] any available empty payload field” in claims 1 and 3, and the term 
TELCORDIA TECH v. CISCO SYSTEMS 12

“inserting means” in claim 4, this court affirms the judgment of non-infringement of the ’306 patent. 

A. 

Claim construction is an issue of law that this court 

reviews without deference. Cybor Corp. v. FAS Techs., 

Inc., 138 F.3d 1448, 1455-56 (Fed. Cir. 1998) (en banc). 

The claim terms “are generally given their ordinary and 

customary meaning.” Phillips v. AWH Corp., 415 F.3d 

1303, 1312 (Fed. Cir. 2005) (en banc) (quotation omitted). 

“[T]he claims themselves provide substantial guidance as 

to the meaning of particular claim terms.” Id. at 1314. 

Also, a patent’s specification “is always highly relevant to 

the claim construction analysis.” Id. at 1315 (quotation 

omitted). Courts should also consider prosecution history 

of the asserted patents. Id. at 1317. However, because 

prosecution history represents an ongoing negotiation 

between the United States Patent and Trademark Office 

and the inventor, “it often lacks the clarity of the specification and thus is less useful for claim construction 

purposes.” Id.

B. 

As noted, claims 1, 3, and 4 of the ’306 patent claim “a 

transmission overhead field containing frame timing 

information and an empty payload field.” The district 

court construed the term “empty payload field” to mean “a 

payload field that is empty of source data, but including 

bit signals of some kind, i.e. garbage bits.” Telcordia 

Techs., Inc. v. Cisco Sys., Inc., No. 04-cv-876, slip. op. at 6 

(D. Del. June 22, 2006) (“Claim Construction Order”). The 

parties dispute whether the claim construction includes 

the explanatory phrase “i.e. garbage bits,” which, according to the parties, limits the “bit signals of some kind” to 

“bits that serve no purpose other than place-holding.” 
13 TELCORDIA TECH v. CISCO SYSTEMS

The empty payload fields are “empty” of data packets 

and therefore have non-source bit signals only. The 

specification explains that “a train of DTDM frames with 

empty payload fields . . . has a bit rate which defines a 

basic backbone transmission rate for the DTDM system.” 

’306 patent col.7 ll.27-30. Therefore, the bit signals help 

the DTDM system maintain a bit stream even when it is 

not transmitting data from an information source. The 

specification does not specify where in the frame the “bit 

rate” is stored nor does it specify the type of non-source 

bits used to maintain the bit rate. Therefore, nothing in 

the ’306 patent restricts the bit signals in the empty 

payload field to ones that serve no purpose other than 

place-holding. 

The district court apparently took the explanatory 

phrase from an ad lib comment made during an oral 

hearing at the Federal Circuit. In Bell Communications 

Research, Inc. v. FORE Systems, Inc., Nos. 02-1083, 02-

1084, 2003 WL 1720080 (Fed. Cir. Mar. 27, 2003), Bell 

Communications Research, Inc., now known as Telcordia, 

asserted the ’306 patent against another defendant. This 

court reviewed a district court’s construction of the term 

“empty payload field” in the ’306 patent. Id. In that case, 

the district court had explained that “a frame’s payload 

has zero data in it.” Id. at *6. During oral hearing, Bell 

Communications agreed with Circuit Judge Bryson’s 

characterization of bits in the “empty payload fields” as 

“garbage:” 

Judge Clevenger: Can we come back to the empty 

payload field? “Empty” seems to me . . . the common meaning of the word “empty” means there is 

nothing there. So, you are saying that there is 

something in the written description that tells me 

what empty means? 
TELCORDIA TECH v. CISCO SYSTEMS 14

Bell Communications’s Counsel: I am saying . . . . 

Judge Clevenger: Where in the written description? 

Bell Communications’ Counsel: A144, column 7, 

lines 29-35. And, what you will see there at that 

point . . . . 

Judge Clevenger: There is a bit rate. 

Bell Communications’s Counsel: It says, “this 

train.” It is talking about empty payload field. 

“This train 10 has a bit rate.” In other words, it’s 

empty, but it has a bit rate. Because in order to 

have . . . sometimes there won’t be a packet ready. 

The stream must continue. There must be a bit in 

the stream. It just won’t be a data bit, it won’t be 

a source data bit. It will be a bit. And it will have 

information in it, but it won’t be source information. 

Judge Bryson: It would just be garbage, I take it. 

I mean it will just be 1’s and 0’s that have no relationship to the stream of any information that’s 

coming in from the source. 

Bell Communications’s Counsel: Exactly, Your 

Honor. 

The issue on appeal, at least initially, seemed to be 

whether the district court actually meant “no bit signals 

of any kind” when it said “zero data.” Id. At oral hearing, 

however, Fore Systems, Inc. stated its understanding that 

“‘zero data’ encompasse[d] various bit signals that might 

maintain the stated transmission rate of a bit stream, 

including ‘placeholders’ or ‘garbage bits.’” Bell Commc’ns, 

2003 WL 1720080, at *6. Because the parties’ agreement 

on this broader interpretation of “zero data” rendered the 
15 TELCORDIA TECH v. CISCO SYSTEMS

claim construction issue moot, this court declined to refine 

the district court’s construction. Id. 

The claim construction issue on appeal in the present 

case—whether the empty payload field only has bits that 

act as placeholders—is different from the one in Bell 

Communications—whether the empty payload field has 

any bits at all. Circuit Judge Bryson’s comments, therefore, are not directly relevant to the specific issue in the 

present case. The district court erred by limiting the claim 

scope based on the ad lib comment from the bench. 

In addition, contrary to Cisco’s assertion, Telcordia 

has not changed its proposed claim construction of “empty 

payload field.” In Bell Communications, Telcordia agreed 

that the empty payload fields only have “garbage bits” 

because it understood the phrase “garbage bits” to mean 

bits with “no relationship to the stream of any information that’s coming in from the source.” In the present 

case, Telcordia disputes the claim construction with the 

phrase “garbage bits” because the district court apparently meant “non-source bit signals that serve no purpose 

other than place-holding.” Thus, Telcordia is not precluded from making the claim construction arguments 

that it makes now. 

Accordingly, “empty payload field” means “a payload 

field that is empty of source data, but includes bit signals 

of some kind.” 

C. 

As noted, claim 1 of the ’306 patent claims “such that 

data in packetized format from any of said sources is 

written into any available empty payload field of any of 

said frames.” Claim 3 recites “such that a packet from 

any of said sources is inserted into any available empty 

payload field of any of said frames.” Claim 4 recites 
TELCORDIA TECH v. CISCO SYSTEMS 16

“inserting each of said packets comprised of data from one 

of said plurality of sources into any empty payload field of 

any of said frames available to said inserting means.” 

The district court construed all three claim elements to 

require that the “packets are only put into frames which 

are empty.” Claim Construction Order at 6-7. The district court further clarified that the claims encompass 

only one packet per frame. Telcordia Techs., Inc. v. Cisco 

Sys., Inc., 514 F. Supp. 2d 598, 606 (D. Del. 2007). Each 

SONET frame in the accused products carries multiple 

ATM cells or packets. Id. Telcordia therefore concedes on 

appeal that it cannot prove infringement if the asserted 

claims encompass only one packet per frame. 

This court agrees with the district court’s construction 

that each frame in the DTDM bit stream can carry only 

one data packet. The specification clearly limits the 

disclosed mechanism to one packet per frame. 

Figure 2, which “illustrates the formation of a DTDM 

bit stream,” ’306 patent col.7 ll.14-15 (emphasis added), 

shows a DTDM assembler inserting one packet into each 

empty payload field. Also, the DTDM assembler’s structure only allows it to insert one packet per frame. The 

DTDM assembler reads data from a FIFO queue of data 

packets if two conditions are met. The first condition is 

that at least one full packet is stored in the FIFO queue. 

The second condition is that “the incoming DTDM frame . 

. . is not already occupied by a valid packet, i.e. the incoming DTDM frame is empty.” Id. at col. 9 ll.38-41. Thus, 

an “empty” frame is one that “is not already occupied by a

valid packet.” Id. at col.9 ll.38-41 (emphasis added). If 

the presence of one packet makes a payload field not 

“empty,” the next packet, which must be inserted into an 

empty DTDM frame, must wait for the next available 

frame. Therefore, the DTDM assembler cannot insert 

more than one data packet into a frame. 
17 TELCORDIA TECH v. CISCO SYSTEMS

Moreover, the specification further explains that 

when the FIFO queue has a packet ready, it “triggers an 

enable signal . . . to be asserted for the whole frame 

transmission period allowing the data packet to be moved 

from the FIFO through the framer and into the DTDM bit 

stream.” Id. at col.9 ll.42-47 (emphasis added). Only one 

data packet can move from the FIFO queue to the DTDM 

bit stream during “the whole frame transmission period,” 

indicating that each frame can store only up to one 

packet. By repeatedly describing the inventive DTDM 

mechanism as one that only allows one packet per frame, 

“the patentee has demonstrated a clear intention to limit 

the claim scope using words or expressions of manifest 

execution or restriction.” Liebel-Flarsheim Co. v. Medrad, 

Inc., 358 F.3d 898, 905 (Fed. Cir. 2004) (internal quotation omitted). 

This court recognizes that during the prosecution of 

the ’306 patent, the applicant made statements suggesting that a frame may be able to store more than one 

packet: 

[A]n empty payload field of each frame may be 

filled with a data packet including a header. [...] 

In certain cases, it may be possible for a payload 

field of a frame to have the capacity for more than 

one packet. 

Although this statement suggests that “it may be possible 

for a payload field” to contain multiple data packets, the 

specification does not disclose any mechanisms that would 

allow more than one packet per frame. These prosecution 

history comments cannot trump the plain language of the 

claims and the direct teaching of the specification. See

Biogen Inc. v. Berlex Labs., Inc., 318 F.3d 1132, 1140 (Fed. 

Cir. 2003) (“Representations during prosecution cannot 

enlarge the content of the specification . . . .”). 
TELCORDIA TECH v. CISCO SYSTEMS 18

Accordingly, the ’306 patent discloses a DTDM 

mechanism in which each frame can store only one data 

packet. This court agrees with the district court’s claim 

constructions of the “such that” limitation in claims 1 and 

3, and the “inserting means” limitation in claim 4. Because Telcordia concedes that it cannot prove infringement based on these claim constructions, this court 

affirms the district court’s grant of summary judgment of 

non-infringement. 

IV. 

“A party seeking a declaratory judgment of invalidity 

presents a claim independent of the patentee’s charge of 

infringement.” Cardinal Chem. Co. v. Morton Int’l, 508 

U.S. 83, 96 (1993). Therefore, this court’s affirmance of 

the district court’s non-infringement findings as to the 

’306 patent does not moot Cisco’s invalidity counterclaim 

on cross-appeal. See Old Town Canoe Co. v. Confluence 

Holdings Corp., 448 F.3d 1309, 1318 (Fed. Cir. 2006). 

This court reaches Cisco’s argument that the asserted 

claims of the ’306 patent are invalid as independently 

anticipated by two prior art publications: (1) Description 

of FasNet by Limb et al. (“FasNet”); and (2) “A 

packet/circuit switch” by Budrikis et al. (“Budrikis”). 

The district court denied Cisco’s JMOL motion on invalidity of the ’306 patent solely on the basis that a reasonable jury could conclude that “the bits used in FasNet 

and Budrikis were intentionally placed with some purpose, and thus, were not garbage bits.” Telcordia, 592 F. 

Supp. 2d at 744. As noted, this court agrees with Telcordia that the “garbage bits” limitation improperly limits 

the scope of the asserted claims. Because the sole basis 

on which the district court based its decision is no longer 

valid, this court remands to the district court for recon-
19 TELCORDIA TECH v. CISCO SYSTEMS

sideration of Cisco’s invalidity counterclaim under the 

revised claim construction. 

V. 

Title 35 provides that “[t]he specification shall conclude with one or more claims particularly pointing out 

and distinctly claiming the subject matter which the 

applicant regards as his invention.” 35 U.S.C. § 112, ¶ 2. 

For a means-plus function claim to satisfy the definiteness requirement, the written description must clearly 

link or associate structure to the claimed function. Biomedino, LLC v. Waters Techs. Corp., 490 F.3d 946, 950 

(Fed. Cir. 2007). Whether the written description adequately sets forth the structure corresponding to the 

claimed function must be considered from the perspective 

of a person skilled in the art. Intel Corp. v. VIA Techs., 

Inc., 319 F.3d 1357, 1365-66 (Fed. Cir. 2003). “The question is not whether one of skill in the art would be capable 

of implementing a structure to perform the function, but 

whether that person would understand the written description itself to disclose such a structure.” Tech. Licensing Corp. v. Videotek, Inc., 545 F.3d 1316, 1338 (Fed. Cir. 

2008). “While corresponding structure need not include all 

things necessary to enable the claimed invention to work, 

it must include all structure that actually performs the 

recited function.” Default Proof Credit Card Sys. v. Home 

Depot U.S.A., Inc., 412 F.3d 1291, 1298 (Fed. Cir. 2005). 

“A determination of claim indefiniteness is a legal conclusion that is drawn from the court’s performance of its duty 

as a construer of patent claims.” Personalized Media 

Commc’ns, L.L.C. v. Int’l Trade Comm’n, 161 F.3d 696, 

705 (Fed. Cir. 1998). 

The district court determined that the term “monitoring means” was a means-plus function term pursuant to 

35 U.S.C. § 112, ¶ 6. The district court identified the 
TELCORDIA TECH v. CISCO SYSTEMS 20

function of the “monitoring means” to be “evaluating the 

integrity of the multiplexed subrate communications on 

the first ring and the second ring,” and the corresponding 

structure for that function to be “the circuitry at a controller that determines if a defect exists with the multiplexed 

subrate communications,” and all equivalents thereof. 

Claim Construction Order at 2-3. 

The written description of the ’763 patent adequately 

discloses the structure for the monitoring means in the 

node-to-node communication system. Each node has two 

controllers, which are connected to different communication rings. As each node monitors and evaluates the 

integrity of the signals arriving at the node, the controllers insert error signals onto the channels when a major 

line fault occurs: 

Each node continuously monitors and evaluates 

the integrity of the multiplexed subrate signals 

arriving at the node. Illustratively, this could be 

accomplished by detecting the absence of a carrier 

signal in an analog signal environment, or the 

lack of any incoming signal in a digital environment. When node 1 recognizes major line fault 

122 in ring 100, controller 118 inserts an error 

signal onto the six subrate channels. This could 

illustratively be accomplished by inserting a 

string of 1’s on each channel in a digital environment. Node 4 performs the identical activity by 

similarly placing an error signal on the six 

subrate channels of ring 101. 

’763 patent col.3 ll.4-17. The nodes have controllers and 

selectors; those selectors cannot recognize any errors in 

the subrate signals until the signals reach the destined 

node. Therefore, the controller must monitor the incoming signals for error; otherwise, the controller would not 
21 TELCORDIA TECH v. CISCO SYSTEMS

be able to insert error signals onto the subrate channels. 

Dr. Prucnal, Telcordia’s expert, also testified that controllers 117 and 118 and their circuitry are the structure 

associated with the function of the monitoring means. 

Thus, the district court did not err by finding that an 

ordinary artisan would understand the written description to clearly link or associate the controller with the 

claimed function. 

As Cisco notes, the figures of the ’763 patent show the 

controller’s circuit as a black box, i.e., nothing in the 

figures describes the details of its inner circuitry. 

“[H]owever, the absence of internal circuitry in the written description does not automatically render the claim 

indefinite.” Tech. Licensing, 545 F.3d at 1338. As noted, 

claim definiteness depends on the skill level of an ordinary artisan. Intel, 319 F.3d at 1365-66. Therefore, the 

specification need only disclose adequate defining structure to render the bounds of the claim understandable to 

an ordinary artisan. Id. (holding that the internal circuitry of an electronic device need not be disclosed in the 

specification if one of ordinary skill in the art would 

understand how to build and modify the device). Here, 

Dr. Prucnal testified that an ordinary artisan would know 

how to interpret the specification and actually build a 

circuit. The record shows that an ordinary artisan would 

have recognized the controller as an electronic device with 

a known structure. Therefore, the specification along 

with the figures shows sufficient structure to define the 

claim terms for an ordinarily artisan in the relevant field. 

Cisco faults Telcordia for not presenting sufficient 

evidence that the patent links the controller with the 

claimed function of the monitoring means. Cisco, in 

particular, challenges Dr. Prucnal’s testimony that the 

circuitry in the controller corresponds to the monitoring 

means. However, patents are presumed to be valid, and 
TELCORDIA TECH v. CISCO SYSTEMS 22

so, Cisco bears the burden of proving that an ordinary 

artisan would not understand the disclosure. 35 U.S.C. 

§ 282; see Aero Prods. Int'l, Inc. v. Intex Rec. Corp., 466 

F.3d 1000, 1015 (Fed. Cir. 2006). The record shows that 

Cisco did not show that an ordinary artisan would not 

understand the link between the controller and the monitoring function. Therefore, this court affirms the district 

court’s decision to deny Cisco’s JMOL motion that the 

asserted claims of the ’763 patent are indefinite. 

VI. 

A. 

Lastly, this court addresses the district court’s damages decisions. In reviewing damages awards in patent 

cases, this court gives “broad deference to the conclusions 

reached by the finder of fact.” Monsanto Co. v. McFarling, 

488 F.3d 973, 981 (Fed. Cir. 2007). This court reviews a 

district court’s damages decision for “an erroneous conclusion of law, clearly erroneous factual findings, or a clear 

error of judgment amounting to an abuse of discretion.” 

Mars, Inc. v. Coin Acceptors, Inc., 527 F.3d 1359, 1372 

(Fed. Cir. 2008). 

B. 

Cisco’s challenge to the district court’s damages decisions largely stems from its argument that the jury’s 

damages award is a paid-up, lump-sum licensing fee, and 

that the district court erred by granting Telcordia additional relief beyond the jury verdict. 

The verdict form asked: 

If you have found any claim of Telcordia U.S. Patent No. 4,835,763 or U.S. Patent No. Re. 36,633 to 

be both valid and infringed by Cisco, please iden-
23 TELCORDIA TECH v. CISCO SYSTEMS

tify the amount of monetary damages that will 

compensate Telcordia for Cisco’s infringement. 

The jury entered “$6,500,000 (6.5 MIL)” on the verdict 

form. The verdict form is unclear whether the jury compensated Telcordia only for Cisco’s past infringement or 

for both past and ongoing infringement. 

During the trial, the parties presented three sets of 

damages numbers to the jury. Telcordia’s damages expert 

testified that the proper damages award should be based 

on a running royalty. Cisco’s expert testified that the 

award should be based on a lump-sum, paid-up license. 

Cisco’s expert also applied a running royalty analysis to 

show the differences between Telcordia’s and Cisco’s 

approaches to damages. Id. To complicate the matter 

further, the parties also presented different royalty rates 

and royalty bases. Therefore, it is unclear whether the 

jury based its award on a lump-sum, paid-up license, 

running royalty, some variation or combination of the 

two, or some other theory. 

District courts have broad discretion to interpret an 

ambiguous verdict form, because district courts witness 

and participate directly in the jury trial process. The 

district court was in a position to assess whether the 

verdict figure represented past infringement as well as 

ongoing infringement. In the absence of an express 

statement in the verdict, this court cannot determine 

whether the jury compensated Telcordia for all of Cisco’s 

infringing activities. The $6.5 million award is closer to 

$5 million proposed by Cisco for past and ongoing infringement than $75 million proposed by Telcordia for 

past infringement only. However, neither party proposed 

the exact $6.5 million figure. In any event, this court 

holds that the district court’s finding that the jury’s 

verdict compensates Telcordia only for past infringement 
TELCORDIA TECH v. CISCO SYSTEMS 24

is not clearly erroneous. In the circumstances of this case, 

this court finds that the district court did not abuse its 

discretion in interpreting the verdict form. 

C. 

Title 35 provides for the calculation of damages “together with interest . . . as fixed by the court.” 35 U.S.C. 

§ 284. In patent infringement cases, “prejudgment interest should be awarded under § 284 absent some justification for withholding such an award.” General Motors 

Corp. v. Devex Corp., 461 U.S. 648, 657 (1983). Cisco 

asserts that the jury’s damages award includes prejudgment interest, thereby barring its award under section 284. For the same reasons, the verdict form is 

ambiguous as to whether the jury’s damages award 

includes prejudgment interest. Because the district court 

did not clearly err by concluding that the jury’s damages 

award did not include prejudgment interest, the district 

court’s award of interest under section 284 does not 

constitute an impermissible double recovery. 

D. 

“Under some circumstances, awarding an ongoing 

royalty for patent infringement in lieu of an injunction 

may be appropriate.” Paice LLC v. Toyota Motor Corp., 

504 F.3d 1293, 1314 (Fed. Cir. 2007). If the district court 

determines that a permanent injunction is not warranted, 

the district court may, and is encouraged, to allow the 

parties to negotiate a license. Id. at 1315. The district 

court may step in to assess a reasonably royalty should 

the parties fail to come to an agreement. Id.

In this case, after declining Telcordia’s motion for 

permanent injunction, the district court directed the 

parties to negotiate a reasonable royalty for ongoing 

infringement. An award of an ongoing royalty is appro-
25 TELCORDIA TECH v. CISCO SYSTEMS

priate because the record supports the district court’s 

finding that Telcordia has not been compensated for 

Cisco’s continuing infringement. Therefore, the district 

court did not abuse its discretion by directing the parties 

to negotiate the terms of the appropriate royalty. 

Accordingly, this court affirms the district court’s 

grant of an accounting and prejudgment interest. As the 

district court properly instructed the parties to negotiate 

the royalty, this court remands to the district court so 

that the parties can complete the royalty negotiation 

process. If the parties cannot reach an agreement, the 

district court should step in and assist or calculate on its 

own the appropriate rate. Telcordia and Cisco will have 

an opportunity to appeal the royalty set by the district 

court. 

VII. 

Accordingly, this court vacates the district court’s denial of Cisco’s JMOL motion on invalidity of the ’306 

patent and remands for determination of the validity 

issue. This court also remands to allow the parties to 

negotiate the terms of the royalty. In all other respects, 

this court affirms. 

AFFIRMED-IN-PART, VACATED-IN-PART, and 

REMANDED. 

COSTS

No Costs. 
United States Court of Appeals 

for the Federal Circuit 

__________________________ 

TELCORDIA TECHNOLOGIES, INC., 

Plaintiff-Appellant, 

v. 

CISCO SYSTEMS, INC., 

Defendant-Cross Appellant. 

__________________________ 

2009-1175, -1184 

__________________________ 

Appeal from the United States District Court for the 

District of Delaware in case no. 04-CV-876, Chief Judge 

Gregory M. Sleet. 

__________________________ 

PROST, Circuit Judge, dissenting-in-part. 

I respectfully dissent on the narrow issue of indefiniteness discussed in Part V of the majority opinion in the 

case. I do not agree that the patent disclosure here 

clearly links the structure of the controller with the 

claimed function of “evaluating the integrity of the multiplexed subrate communications on the first ring and the 

second ring,” to the extent required by this court’s precedent. 

The patent specification describes the invention as 

comprising nodes. Each node has a plurality of parts, 

including a controller and a selector. The disclosure 
TELCORDIA TECH v. CISCO SYSTEMS 2

states that “the node continuously monitors and evaluates 

the integrity of the multiplexed subrate signals arriving 

at the node.” U.S. Patent No. 4,835,763 (“’763 patent”) 

col.3 ll.4-17. The disclosure only associates the monitoring function with the node as a whole. At no point does 

the specification reveal that the structure within the node 

that performs the monitoring task is the circuitry of the 

controller. 

Furthermore, the specification dedicates ample text to 

describing the function of the controller. The description 

explains that the controller inserts error signals when the 

node detects a fault in the ring. Id. Nowhere does the 

specification mention that the controller is also the part of 

the node that monitors and detects the faults when the 

multiplexed subrate signals arrive. Indeed, by attributing 

certain functions to the node as a whole and other functions specifically to the controller, the disclosure implies 

that the node structure associated with the monitoring 

means is distinct from the controller structure associated 

with the insertion of error signals. 

The majority holds that one of skill in the art would 

understand that the selector component is not capable of 

performing the monitoring function, and by process of 

elimination would deduce that the controller is the structural component of the node associated with the claimed 

function. Majority Op. at 20-21. It is not enough, in my 

view, that a skilled artisan can follow the clues in the 

patent and solve the mystery of what structure must 

perform the claimed function. See Tech. Licensing Corp. 

v. Videotek, Inc., 545 F.3d 1316, 1338 (Fed. Cir. 2008). 

Our precedent requires that the specification clearly link 

a particular structure with a claimed function. See Biomedino, LLC v. Waters Techs. Corp., 490 F.3d 946, 950 

(Fed. Cir. 2007); Tech. Licensing, 545 F.3d at 1338. 
3 TELCORDIA TECH v. CISCO SYSTEMS

Accordingly, I would hold that the term “monitoring 

means” is indefinite under 35 U.S.C. § 112 for failing to 

disclose a structure associated with the claimed function, 

and thus hold the asserted claim of the ’763 patent invalid.