Exhibit 10.10. Second Loan Modification by and between Zoom Telephonics, 
INC, and Fleet National Bank


                                        SECOND LOAN MODIFICATION AGREEMENT


         This Second Loan Modification  Agreement ("this  Agreement") is made as
of November 17, 1998 between Zoom Telephonics, Inc., a Delaware corporation (the
"Borrower")  and  Fleet  National  Bank  (the  "Bank").  For good  and  valuable
consideration,  receipt and  sufficiency of which are hereby  acknowledged,  the
Borrower and the Bank act and agree as follows:

         1.  Reference  is made to:  (i) that  certain  letter  agreement  dated
January  17,  1997  between  the  Borrower  and the  Bank,  as  amended  by Loan
Modification Agreement dated as of November 13, 1997 (as so amended, the "Letter
Agreement");  (ii) that certain $5,000,000 face principal amount promissory note
dated  November  13, 1997 (the "1997  Revolving  Note") made by the Borrower and
payable to the order of the Bank; (iii) that certain Guaranty Agreement dated as
of January 17, 1997 (the "FSC  Guaranty")  from Zoom  Telephonics  Foreign Sales
Corporation  ("FSC") to the Bank; (iv) that certain Guaranty  Agreement dated as
of  January  17,  1997  (the  "Tribe   Guaranty")  from  Tribe  Computer  Works,
Incorporated  ("Tribe")  to the Bank;  (v) that certain  Inventory  and Accounts
Receivable  Security  Agreement  dated  November  13,  1997 (the "Zoom  Security
Agreement")  given by the Borrower to the Bank; (vi) that certain  Inventory and
Accounts  Receivable  Security  Agreement  dated  November  13, 1997 (the "Tribe
Security  Agreement")  given by Tribe to the Bank; (vii) that certain  Inventory
and Accounts  Receivable  Security  Agreement  dated November 13, 1997 (the "FSC
Security  Agreement")  given  by  FSC to  the  Bank;  and  (viii)  that  certain
$5,000,000  face  principal  amount  promissory  note of even date herewith (the
"1998  Revolving  Note")  made by the  Borrower  and payable to the order of the
Bank.  The Letter  Agreement,  The FSC Guaranty,  the Tribe  Guaranty,  the Zoom
Security Agreement, the Tribe Security Agreement, the FSC Security Agreement and
the 1998 Revolving Note hereinafter  collectively  referred to as the "Financing
Documents".  The  aforesaid  November  13, 1997 Loan  Modification  Agreement is
hereinafter referred to as the "First Modification".

         2. The Letter  Agreement  is hereby  amended,  effective as of the date
hereof:

         a. By  inserting  into the first  grammatical  paragraph  of the Letter
Agreement, immediately after the first sentence thereof, the following:

                  "This letter agreement provides for (1) a $5,000,000  facility
                  for  Revolving  Loans on the  terms and  conditions  set forth
                  below,  plus (2) a $500,000  facility for letters of credit on
                  the terms and conditions set forth below,  plus (3) a $500,000
                  facility  for  Foreign  Exchange  Contracts  on the  terms and
                  conditions set forth below."

         b. By  deleting  from the second  sentence of Section 1.1 of the Letter
Agreement the words  "Aggregate Bank  Liabilities"  and by substituting in their
stead the following:

                  "total principal amounts of the Revolving Loans outstanding"

         c. By deleting in its  entirety  the fourth  sentence of Section 1.1 of
the Letter Agreement and by substituting in its stead the following:

                  "The  Revolving  Loans  shall  be  evidenced  by that  certain
                  $5,000,000   face  principal   amount   promissory  note  (the
                  `Revolving Note') dated November 17, 1998 made by the Borrower
                  and payable to the order of the Bank."

As a result,  all  references  in the Letter  Agreement to a  
"Revolving  Note" will be deemed to refer to the 1998
Revolving Note.

         d. By  inserting  into the first  sentence of the second  paragraph  of
Section 1.9 of the Letter Agreement,  immediately after the words "any letter of
credit", the following:

                  "and/or with respect to any of the other Obligations"

         e. By  deleting  the  period at the end of the second  sentence  of the
second  paragraph of Section 1.9 of the Letter  Agreement and by substituting in
its stead the following:

                  "or with respect to any of the other Obligations."

         f. By  inserting  into each of the first and  second  sentences  of the
third paragraph of Section 1.9 of the Letter  Agreement,  immediately  after the
words "any letter of credit", in each place where same appear, the following:

                  "and/or with respect to any of the other Obligations"

         g. By  inserting  into the third  sentence  of the third  paragraph  of
Section 1.9 of the Letter Agreement,  immediately after the words "the Revolving
Note", the following:

                  "and/or with respect to any letter of credit or any of
the other Obligations"

         h. By  deleting  from the  third  sentence  of the third  paragraph  of
Section  1.9 of the Letter  Agreement  the words "75 State  Street,  Boston,  MA
02109" and by substituting in their stead the following:

                  "One Federal Street, Boston, MA  02110"

         i.  By  deleting  in its  entirety  the  fifth  sentence  of the  third
paragraph  of Section 1.9 of the Letter  Agreement  and by  substituting  in its
stead the following:

                  "All  monies  received  by the Bank shall be applied  first to
                  fees,  charges  and  expenses  payable  to the Bank under this
                  letter  agreement,  any  Note  and/or  any of the  other  Loan
                  Documents  and/or with respect to any letter of credit  and/or
                  with respect to any other  Obligation,  next to interest  then
                  accrued   on   account  of  any  Loans  or  letter  of  credit
                  reimbursement  obligations or any of the other Obligations and
                  only thereafter to principal of the Loans and letter of credit
                  reimbursement obligations and other Obligations, being applied
                  against the Loans, such reimbursement  obligations and/or such
                  other  Obligations in such order as the Borrower may designate
                  (and,  failing such  designation,  being applied first against
                  the letter of credit reimbursement  obligations and such other
                  Obligations, and thereafter against the Revolving Loans)."

         j. By  inserting  into the last  sentence of Section  1.9,  immediately
after the words "the Revolving Note", the following:

                  "and/or with respect to any of the other Obligations"

         k. By  deleting in its  entirety  the  proviso  appearing  in the first
sentence of Section  1.10 of the Letter  Agreement  and by  substituting  in its
stead the following:

                  ";  provided  that at the time of each such issuance and after
                  giving   effect   thereto  (A)  the  total  Letter  of  Credit
                  Liabilities  will not exceed  $500,000  and (B) the  Aggregate
                  Bank Liabilities will not exceed the then effective  Borrowing
                  Base."

         l. By inserting into the second  grammatical  paragraph of Section 1.11
of the Letter Agreement,  immediately after the word "Loan", in each place where
same appears (whether in the introductory  clause of said paragraph or in either
of clause (a) or clause (b) thereof), the following:

                  "(including, without limitation, issuance of any Foreign 
Exchange Contract)"

         m. By  inserting  into the  first  sentence  of the last  paragraph  of
Section 1.11 of the Letter Agreement, immediately after the word "Loan", in each
place where same appears, the following:

                  "(or the issuance of any Foreign Exchange Contract)"

         n. By deleting in its  entirety  Section  1.12 of the Letter  Agreement
(said  Section  having  been  inserted  by  the  First   Modification)   and  by
substituting in its stead, the following:

                  "1.12.  Foreign  Exchange.  The Bank is also  providing to the
                  Borrower a facility (the `F/X  Facility') for forward  foreign
                  exchange contracts (`Foreign Exchange  Contracts') between the
                  Bank and the  Borrower.  The F/X Facility  will have an expiry
                  date of  October  1,  1999 and will  permit  Foreign  Exchange
                  Contracts in a maximum  aggregate  notional amount of $500,000
                  outstanding  at any one  time;  provided  that (i)  each  such
                  Foreign Exchange  Contract will be at such pricing as the Bank
                  and the  Borrower  may agree at the time of  execution of such
                  Foreign Exchange  Contract,  (ii) the  documentation  for each
                  such Foreign Exchange Contract will be in such form as is then
                  customarily  used by the Bank for  transactions  of this type,
                  (iii)  the  Foreign  Exchange  Contracts  will  be used by the
                  Borrower to minimize  its exposure to the  fluctuation  of the
                  value of  those  foreign  currencies  in  which  payments  are
                  expected to be made to the  Borrower by  customers or in which
                  the Borrower is required to make  payments to  suppliers,  and
                  (iv) the F/X Exposure will at no time exceed $500,000. As used
                  herein, the `F/X Exposure' as determined at any date means the
                  sum of (i) all amounts  then owed by the  Borrower to the Bank
                  in  connection  with   settlement  of  any  Foreign   Exchange
                  Contract,  plus (ii) the maximum two-day settlement amount for
                  all then outstanding Foreign Exchange Contracts."

         o. By  inserting  into the  introductory  clause of Section  2.1 of the
Letter Agreement, immediately after the words "letters of credit hereunder", the
following:

                  "and/or issue Foreign Exchange Contracts"

         p.       By deleting in their entireties  Sections
 3.7 - 3.10,  inclusive, 
of the Letter Agreement and by
substituting in their stead the following:

                  "3.7.  Debt to Capital Base.  The Borrower will maintain as at
                  the end of each  fiscal  quarter of the  Borrower  (commencing
                  with its results as at September  30, 1998) on a  consolidated
                  basis a Leverage  Ratio  which  shall be equal to or less than
                  1.0 to 1. As used herein,  `Leverage  Ratio' means,  as at any
                  date  when  same is to be  determined,  the  ratio  of (x) the
                  consolidated   Indebtedness   of  the   Borrower   and/or  its
                  Subsidiaries  then  outstanding  to (y) the then  consolidated
                  Capital Base of the Borrower and its Subsidiaries.

                  3.8. Capital Base. The Borrower will maintain as at the end of
                  each  fiscal  quarter  of the  Borrower  (commencing  with its
                  results as at September 30, 1998) a consolidated  Capital Base
                  which shall be equal to or greater than $32,800,000.

                  3.9.  Reserved.

                  3.10.  Liquidity.  The Borrower will maintain as at the end of
                  each  fiscal  quarter  of the  Borrower  (commencing  with its
                  results as at  September  30,  1998) a Quick Ratio equal to or
                  greater than 2.0 to 1. As used herein,  the `Quick Ratio',  as
                  determined  at any date,  is the ratio of (x) Net Quick Assets
                  at such date to (y) Current  Liabilities  outstanding  as such
                  date."

         q.       By  deleting  the word "and"  appearing  at the end
 of clause  (ix) of Section  4.1 of the Letter
Agreement.

         r.       By deleting the period at the end of Section 4.1 of the
 Letter  Agreement and by  substituting in
its stead the following:

                  "; and (xi) with the prior  written  consent of the Bank (such
                  consent not to be unreasonably  withheld so long as there does
                  not then  exist and would not  result  therefrom  any Event of
                  Default or event or  circumstance  which,  with the passage of
                  time or the giving of notice or both, could become an Event of
                  Default (with compliance with each of ss.ss.3.7,  3.8 and 3.10
                  being  measured  for this  purpose  both as at the  then  most
                  recent fiscal quarter-end and, on a pro forma basis, as at the
                  date   of   incurrence   of   the   relevant   Indebtedness)),
                  Indebtedness which the Borrower may incur from time to time by
                  financing  and/or  refinancing its real estate;  provided that
                  such  Indebtedness  is secured only by a mortgage of such real
                  estate and the aggregate  amount  outstanding at any time does
                  not exceed the fair market value of such real estate."

         s.       By  deleting  the word "or"  appearing  at the end of clause 
 (v) of  Section  4.2 of the  Letter
Agreement.

         t.       By deleting  the period at the en
d of clause (vi) of Section 4.2 of the Letter  Agreement  and by
substituting in its stead the following:

                  "; or (vii)  with  the  Bank's  prior  written  consent  (such
                  consent not to be  unreasonably  withheld),  mortgages  on the
                  Borrower's  real  estate  securing  Indebtedness  specifically
                  permitted by clause (xi) of ss.4.1;  provided that no property
                  of the Borrower other than such real estate is encumbered."

         u. By deleting the period at the end of the last grammatical  paragraph
of Section  4.2 of the Letter  Agreement  and by  substituting  in its stead the
following:

                  ",  except that the  mortgages  described  in clause  (vii) 
 above may  prohibit  junior
                  encumbrances."

         v. By inserting into clause (a) of Section 5.1 of the Letter Agreement,
immediately after the words "issued by the Bank", the following:

                  "or with respect to any Foreign Exchange Contract"

         w. By inserting into clause (b) of Section 5.1 of the Letter Agreement,
immediately after the words "letter of credit", the following:

                  "or any Foreign Exchange Contract"

         x.       By adding to Section 5.4 of the Letter Agreement, at the end
 of such Section, the following:

                  "Upon the  occurrence of any event  described in clause (i) or
                  clause (ii) of the immediately  preceding  sentence,  the Bank
                  may  also  require  the  Borrower  to cash  collateralize  the
                  outstanding F/X Exposure."

         y. By  inserting  into the first  sentence of Section 6.1 of the Letter
Agreement,  immediately after the words "letter of credit issued hereunder", the
following:

                  "and/or any of the other Obligations"

         z. By  inserting  into the first  sentence of Section 6.1 of the Letter
Agreement, immediately after the words "in connection herewith", the following:

                  "or in connection with any of the other Obligations"

         aa.      By changing the notice address of the Bank,  pursuant to 
Section 6.5 of the Letter Agreement,  to
the following:

                  "Fleet National Bank
                   High Technology Division
                   Mail Code: MA OF D07A
                   One Federal Street, 7th Floor
                   Boston, MA  02110
                   Attention:  Scott D. Wheelock, Vice President"

         bb.      By inserting into Section 6.6 of the Letter  Agreement, 
 immediately  after the third sentence of
such Section, the following:

                  "Without limitation of the foregoing generality,

                  (i) The Bank may at any time  pledge all or any portion of its
                  rights under the Loan Documents  (including any portion of the
                  Revolving  Note)  to  any  of the  12  Federal  Reserve  Banks
                  organized  under  Section 4 of the  Federal  Reserve  Act,  12
                  U.S.C.  Section 341. No such pledge or the enforcement thereof
                  shall release the Bank from its  obligations  under any of the
                  Loan Documents.

                  (ii) The Bank  shall have the  unrestricted  right at any time
                  and from time to time, and without the consent of or notice to
                  the Borrower, to grant to one or more banks or other financial
                  institutions (each, a `Participant')  participating  interests
                  in the Bank's  obligation to lend hereunder  and/or any or all
                  of the Loans held by the Bank  hereunder.  In the event of any
                  such  grant  by the  Bank  of a  participating  interest  to a
                  participant,  whether or not upon notice to the Borrower,  the
                  Bank  shall  remain  responsible  for the  performance  of its
                  obligations  hereunder and the Borrower shall continue to deal
                  solely  and  directly  with  the Bank in  connection  with the
                  Bank's rights and obligations hereunder.  The Bank may furnish
                  any information concerning the Borrower in its possession from
                  time  to  time  to  prospective  assignees  and  Participants;
                  provided  that the Bank  shall  require  any such  prospective
                  assignee or  Participant  to agree in writing to maintain  the
                  confidentiality  of such information to the same extent as the
                  Bank would be required to maintain such confidentiality."

         cc.      By deleting in its entirety the definition of "Expiration
  Date"  appearing in Section 7.1 of the
Letter Agreement and by substituting in its stead the following:

                  "`Expiration  Date' - October 1, 1999,  unless extended by the
                  Bank,  which extension may be given or withheld by the Bank in
                  its sole discretion."

As a result,  from and after the date  hereof,  for the  purposes  of the Letter
Agreement  and the other  Financing  Documents,  the  "Expiration  Date" will be
deemed to be October 1, 1999.

         dd. By inserting into Section 7.1 of the Letter Agreement,  immediately
before the definition of "F/X Facility" (said definition having been inserted by
the First Modification), the following:

                  "`F/X Exposure' - As defined in ss.1.12 above."

         ee.      By inserting  into Section 7.1 of the Letter  Agreement,
 immediately  before the  definition  of
"Loan Documents", the following:

                  "`Letter of Credit  Liabilities' - At any time, the sum of (i)
                  the then  undrawn  amounts of all letters of credit  issued by
                  the  Bank  for the  account  of the  Borrower,  plus  (ii) all
                  amounts  then drawn on any such letter of credit which at said
                  date  shall  not  have  been  reimbursed  to the  Bank  by the
                  Borrower.

                  `Loan' - Any Revolving  Loan or any other
 extension of credit 
by the Bank to or for the
                  benefit of the Borrower."

         ff. By inserting into the definition of "Loan  Documents"  appearing in
Section  7.1 of the  Letter  Agreement,  immediately  after  the  words  "issued
hereunder", the following:

                  "or to any Foreign Exchange Contract"

         gg.      By deleting in its entirety the  definition of "Maximum  
Revolving  Amount"  appearing in Section
7.1 of the Letter Agreement and by substituting in its stead the following:

                  "`Maximum Revolving Amount' - $5,000,000."

         3. Wherever in any Financing Document, or in any certificate or opinion
to be  delivered  in  connection  therewith,  reference  is  made  to a  "letter
agreement"  or to the  "Letter  Agreement",  from and after the date hereof same
will be deemed to refer to the Letter Agreement, as hereby amended.

         4.  Simultaneously  with the execution and delivery of this  Agreement,
the Borrower is executing and delivering to the Bank the 1998 Revolving Note, in
substitution  for  the  1997  Revolving  Note.  The  1998  Revolving  Note  is a
$5,000,000  promissory note of the Borrower,  substantially in the form attached
hereto as  Exhibit  1.  Wherever  in any of the  Financing  Documents  or in any
certificate  or opinion to be delivered in  connection  therewith,  reference is
made to a "Revolving  Note",  from and after the date hereof same will be deemed
to refer to the 1998 Revolving Note.

         5. Each of Tribe and FSC  confirms  that the Tribe  Guaranty  and Tribe
Security   Agreement   and  the  FSC  Guaranty   and  FSC  Security   Agreement,
respectively,  remain in full  force and  effect  and that  same  guarantee  and
secure,  inter alia,  payment and performance of the Letter Agreement (as hereby
amended)  and the 1998  Revolving  Note.  The  Borrower  confirms  that the Zoom
Security  Agreement  remains in full force and effect and  secures,  inter alia,
payment and performance of the Letter Agreement (as amended hereby) and the 1998
Revolving Note.

         6. In  order to  induce  the Bank to enter  into  this  Agreement,  the
Borrower further represents and warrants as follows:

         a. The  execution,  delivery and  performance of this Agreement and the
1998 Revolving  Note have been duly  authorized by the Borrower by all necessary
corporate and other action,  will not require the consent of any third party and
will not  conflict  with,  violate  the  provisions  of, or cause a  default  or
constitute  an event which,  with the passage of time or the giving of notice or
both,  could  cause a default  on the part of the  Borrower  under  its  charter
documents  or  by-laws  or under any  contract,  agreement,  law,  rule,  order,
ordinance,  franchise, instrument or other document, or result in the imposition
of any lien or  encumbrance  (except  in favor of the Bank) on any  property  or
assets  of the  Borrower.  The  execution,  delivery  and  performance  of  this
Agreement  have been duly  authorized  by each of FSC and Tribe by all necessary
corporate and other action,  will not require the consent of any third party and
will not  conflict  with,  violate  the  provisions  of, or cause a  default  or
constitute  an event which,  with the passage of time or the giving of notice or
both,  could  cause a  default  on the part of FSC or Tribe  under  its  charter
documents  or  by-laws  or under any  contract,  agreement,  law,  rule,  order,
ordinance,  franchise, instrument or other document, or result in the imposition
of any lien or  encumbrance  (except  in favor of the Bank) on any  property  or
assets of FSC or Tribe.

         b. The Borrower has duly executed and delivered  each of this Agreement
and the  1998  Revolving  Note.  Each of FSC and  Tribe  has duly  executed  and
delivered this Agreement.

         c. Each of this  Agreement  and the 1998  Revolving  Note is the legal,
valid and binding obligation of the Borrower,  enforceable  against the Borrower
in accordance with its respective terms. This Agreement is the legal,  valid and
binding obligation of each of FSC and Tribe, enforceable against each of FSC and
Tribe in accordance with its terms.

         d. The  statements,  representations  and warranties made in the Letter
Agreement,  in the Tribe  Guaranty  and/or in the FSC  Guaranty  continue  to be
correct as of the date hereof; except as amended, updated and/or supplemented by
the attached Supplemental Disclosure Schedule.

         e.  Giving  effect  to the  foregoing  amendments,  the  covenants  and
agreements of the Borrower,  FSC and/or Tribe contained in the Letter Agreement,
in the Zoom  Security  Agreement,  in the FSC Security  Agreement,  in the Tribe
Security  Agreement,  in the FSC Guaranty and/or in the Tribe Guaranty have been
complied with on and as of the date hereof.

         f.  Giving  effect  to  the  foregoing   amendments,   no  event  which
constitutes or which,  with notice or lapse of time, or both, could  constitute,
an Event of Default (as defined in the Letter  Agreement)  has  occurred  and is
continuing.

         g. No material  adverse change has occurred in the financial  condition
of the Borrower from that disclosed in the quarterly financial statements of the
Borrower dated September 30, 1998, heretofore furnished to the Bank.

         7. Except as expressly  affected hereby,  the Letter Agreement and each
of the other Financing Documents remains in full force and effect as heretofore.

         8. Nothing  contained herein will be deemed to constitute a waiver or a
release of any provision of any of the Financing  Documents.  Nothing  contained
herein will in any event be deemed to  constitute  an agreement to give a waiver
or release or to agree to any amendment or  modification of any provision of any
of the Financing Documents on any other or future occasion.

         Executed,  as an  instrument  under seal,  as of the day and year first
above written.

                  BORROWER:

                 ZOOM TELEPHONICS, INC.


            By:             /s/ Robert A. Crist
                        Name: Robert A. Crist
                      Title: V.P. Finance & CFO


             By:             /s/ Frank Manning
                            Name: Frank Manning
                           Title: President & CEO


              GUARANTORS:

                           ZOOM TELEPHONICS FOREIGN
                                SALES CORPORATION

                   By:             /s/ Frank Manning
                                  Name: Frank Manning
                               Title: President & CEO


                     TRIBE COMPUTER WORKS, INCORPORATED



                  By:             /s/ Frank Manning
                           Name: Frank Manning
                      Title: President & CEO

Accepted and agreed:
FLEET NATIONAL BANK


By:  /s/ Scott Wheelock
     Name: Scott Wheelock
     Title: Vice President
  SUPPLEMENTAL DISCLOSURE SCHEDULE


                                           [To be provided by Borrower.]