AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON JULY 23, 1999
                                                       REGISTRATION NO. 333-____


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                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                                    FORM S-8

                          REGISTRATION STATEMENT UNDER
                           THE SECURITIES ACT OF 1933

                           EXCEL SWITCHING CORPORATION
             (Exact Name of Registrant as Specified in Its Charter)

      MASSACHUSETTS                                    04-2992806
 (State or Other Jurisdiction of           (I.R.S. Employer Identification No.)
 Incorporation or Organization)

                             255 INDEPENDENCE DRIVE
                                HYANNIS, MA 02601
               (Address of Principal Executive Offices) (Zip Code)
                              --------------------

                   AMENDED AND RESTATED 1997 STOCK OPTION PLAN
                              STOCK OPTION PROGRAM
                                      AND
                          RASCOM, INC. 1996 STOCK PLAN
                            (Full Title of the Plan)
                              --------------------

                                ROBERT P. MADONNA
                       PRESIDENT & CHIEF EXECUTIVE OFFICER
                           EXCEL SWITCHING CORPORATION
                             255 INDEPENDENCE DRIVE
                          HYANNIS, MASSACHUSETTS 02601
                     (Name and Address of Agent For Service)

                                 (508) 862-3000
          (Telephone Number, Including Area Code, of Agent For Service)
                         ------------------------------

                                    Copy to:
       Christopher Stavros, Esq.                     John Hession, Esq.
      EXCEL SWITCHING CORPORATION             TESTA, HURWITZ & THIBEAULT, LLP
        255 Independence Drive              Oliver Street Tower, 125 High Street
     Hyannis, Massachusetts 02601               Boston, Massachusetts 02110
            (508) 862-3000                             (617) 248-7000


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                         CALCULATION OF REGISTRATION FEE

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                                                                                         PROPOSED
                                                                  PROPOSED MAXIMUM       MAXIMUM
                                                  AMOUNT TO BE     OFFERING PRICE       AGGREGATE           AMOUNT OF
     TITLE OF SECURITIES TO BE REGISTERED          REGISTERED         PER SHARE       OFFERING PRICE   REGISTRATION FEE (3)
     ------------------------------------          ----------     ----------------    --------------   --------------------

                                                                                               
AMENDED AND RESTATED 1997 STOCK OPTION PLAN
Common Stock (Par Value $.01 Per Share)              2,000,000      $ 29.125  (1)     $  58,250,000       $  16,193.50

STOCK OPTION PROGRAM
Common Stock (Par Value $.01 Per Share)                450,000      $ 0.00165 (2)     $      742.50       $       0.21

RASCOM, INC. 1996 STOCK PLAN
Common Stock (Par Value $.01 Per Share)                  2,790      $    4.05 (2)     $   11,299.50       $       3.14
Common Stock (Par Value $.01 Per Share)                    379      $    4.50 (2)     $    1,705.50       $       0.47
Common Stock (Par Value $.01 Per Share)                    622      $    6.75 (2)     $    4,198.50       $       1.17

TOTAL:                                               2,453,791                                            $  16,198.49


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(1)    The price of $29.125 per share, which is the average of the high and low
       prices of the Common Stock of the Registrant reported on the Nasdaq
       National Market on July 22, 1999, is set forth solely for purposes of
       calculating the filing fee pursuant to Rule 457(c) and (h) and has been
       used for those shares without a fixed exercise price.

(2)    Such shares are issuable upon exercise of outstanding options with fixed
       exercise prices. Pursuant to Rule 457(h), the aggregate offering price
       and the fee have been computed upon the basis of the price at which the
       options may be exercised. The offering price per share set forth for such
       shares is the exercise price per share at which such options are
       exercisable.

(3)    Calculated pursuant to Section 6(b) of the Securities Act of 1933.


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                                     PART I

              INFORMATION REQUIRED IN THE SECTION 10(a) PROSPECTUS

ITEM 1.  PLAN INFORMATION.

         The documents containing the information specified in this Item 1 will
be sent or given to employees, directors and others as specified by Rule
428(b)(1). In accordance with the rules and regulations of the Securities and
Exchange Commission (the "Commission") and the instructions to Form S-8, such
documents are not being filed with the Commission either as part of this
Registration Statement or as prospectuses or prospectus supplements pursuant to
Rule 424.

ITEM 2.  REGISTRANT INFORMATION AND EMPLOYEE PLAN ANNUAL INFORMATION.

         The documents containing the information specified in this Item 2 will
be sent or given to employees, directors or others as specified by Rule
428(b)(1). In accordance with the rules and regulations of the Commission and
the instructions to Form S-8, such documents are not being filed with the
Commission either as part of this Registration Statement or as prospectuses or
prospectus supplements pursuant to Rule 424.

                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

ITEM 3.  INCORPORATION OF DOCUMENTS BY REFERENCE.

         The following documents filed by the Registrant with the Commission
pursuant to the Securities Exchange Act of 1934, as amended (the "Exchange Act")
are incorporated by reference in this Registration Statement:

         (a)      The Registrant's Annual Report on Form 10-K for the fiscal
                  year ended December 31, 1998, filed pursuant to the Exchange
                  Act which contains audited financial statements for the fiscal
                  year ended December 31, 1998.

         (b)      The Registrant's Quarterly Report on Form 10-Q for the fiscal
                  quarter ended March 31, 1999, filed on May 18, 1999 pursuant
                  to the Exchange Act.

         (c)      The Registrant's Current Report on Form 8-K, dated April 15,
                  1999 and filed on April 23, 1999 pursuant to the Exchange Act.

         (d)      The Registrant's Current Report on Form 8-K, dated May 10,
                  1999 and filed on May 25, 1999 pursuant to the Exchange Act.

         (e)      The section entitled "Description of Registrant's Securities
                  to be Registered," contained in the Registrant's Registration
                  Statement on Form 8-A, filed on October 23, 1997 pursuant to
                  Section 12 of the Exchange Act.

         All documents subsequently filed with the Commission by the Registrant
pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act, prior to
the filing of a post-effective amendment which indicates that all securities
offered herein have been sold or which deregisters all securities then remaining
unsold, shall be




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deemed to be incorporated by reference in this Registration Statement and to be
a part hereof from the date of filing of such documents.


ITEM 4.  DESCRIPTION OF SECURITIES.

         Not applicable.

ITEM 5.  INTEREST OF NAMED EXPERTS AND COUNSEL.

         Not applicable.

ITEM 6.  INDEMNIFICATION OF DIRECTORS AND OFFICERS.

         The Registrant is required by its Restated By-laws and its Restated
Articles of Organization generally to indemnify any director, officer or
employee against all expenses and liabilities reasonably incurred by or imposed
upon such person in connection with any legal action in which such person is
involved by reason of such person's position with the Registrant unless such
person shall have been finally adjudicated in any action, suit or proceeding not
to have acted in good faith in the reasonable belief that such person's action
was in the best interests of the Registrant. The Registrant may pay expenses
incurred by any such person in defending a civil or criminal action or
proceeding in advance of the final disposition of such action upon the
Registrant's receipt of the undertaking of such person to repay such amount if
such person shall be adjudicated not to be entitled to indemnification.

         The Registrant's Restated Articles of Organization include a provision
limiting the personal liability of a director of the Registrant to its
stockholders for monetary damages for breaches of their fiduciary duty except
(i) for any breach of the director's duty of loyalty to the Registrant or its
stockholders, (ii) for acts or omissions not in good faith or which involve
intentional misconduct or a knowing violation of law, (iii) under section
sixty-one or sixty-two of Chapter 156B of the Massachusetts General Laws, or
(iv) for any transaction from which the director derived an improper benefit.

         The Registrant maintains directors and officers liability insurance for
the benefit of its directors and certain of its officers.

ITEM 7.  EXEMPTION FROM REGISTRATION CLAIMED.

         Not applicable.




                                       4


ITEM 8.  EXHIBITS.



EXHIBIT NO.       DESCRIPTION OF EXHIBIT

               
4.1               Restated Articles of Organization of the Registrant (filed as
                  Exhibit 3.1 to the Registrant's Registration Statement on Form
                  S-1 (Registration No. 333-35791) and incorporated herein by
                  reference).

4.2               Restated By-Laws of the Registrant (filed as Exhibit 3.2 to the
                  Registrant's Annual Report filed on Form 10-K on
                  March 31, 1999 and incorporated herein by reference).

4.3               Amended and Restated 1997 Stock Option Plan (filed as Exhibit
                  10.1 to the Registrant's Annual Report filed on Form 10-K on
                  March 31, 1999 and as approved by the stockholders of the
                  Registrant on May 14, 1999 and incorporated herein by
                  reference).

4.4               Form of Non-Qualified Stock Option Agreement under the
                  Registrant's Amended and Restated 1997 Stock Option Plan
                  (filed herewith).

4.5               Rascom, Inc. 1996 Stock Plan (filed as Exhibit 4.3 to the
                  Registrant's Registration Statement on Form S-8 filed with
                  the Commission on May 24, 1999 and incorporated herein
                  by reference).

5.1               Opinion of Testa, Hurwitz & Thibeault, LLP (filed herewith)

23.1              Consent of Arthur Andersen LLP (filed herewith)

23.2              Consent of Testa, Hurwitz & Thibeault, LLP (included in Exhibit 5.1)

24.1              Power of Attorney (included as part of the signature page to this
                  Registration Statement)


ITEM 9.  UNDERTAKINGS.

         (a)      The undersigned Registrant hereby undertakes:

                  (1)      To file, during any period in which offers or sales
                  are being made, a post-effective amendment to this
                  registration statement:

                           (i)      To include any prospectus required by
                           Section 10(a)(3) of the Securities Act of 1933;

                           (ii)     To reflect in the prospectus any facts or
                           events arising after the effective date of the
                           registration statement (or the most recent
                           post-effective amendment thereof) which, individually
                           or in the aggregate, represent a fundamental change
                           in the information set forth in the registration
                           statement. Notwithstanding the foregoing, any
                           increase or decrease in volume of securities offered
                           (if the total dollar value of securities offered
                           would not exceed that which was registered) and any
                           deviation from the low or high end of the estimated
                           maximum offering range may be reflected in the form
                           of prospectus filed with the Commission pursuant to
                           Rule 424(b) if, in the aggregate, the changes in
                           volume and price represent no more than a 20 percent
                           change in the maximum aggregate offering price set
                           forth in the "Calculation of Registration Fee" table
                           in the effective registration statement;

                           (iii)    To include any material information with
                           respect to the plan of distribution not previously
                           disclosed in the registration statement or any
                           material change to such information in the
                           registration statement;


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                  (2)      That, for the purpose of determining any liability
                  under the Securities Act of 1933, each such post-effective
                  amendment shall be deemed to be a new registration statement
                  relating to the securities offered therein, and the offering
                  of such securities at that time shall be deemed to be the
                  initial bona fide offering thereof;

                  (3)      To remove from registration by means of a
                  post-effective amendment any of the securities being
                  registered which remain unsold at the termination of the
                  offering.

                  (4)      If the registrant is a foreign private issuer, to
                  file a post-effective amendment to the registration statement
                  to include any financial statements required by Rule 3-19 of
                  this chapter at the start of any delayed offering or
                  throughout a continuous offering. Financial statements and
                  information otherwise required by Section 10(a)(3) of the Act
                  need not be furnished, provided, that the registrant includes
                  in the prospectus, by means of a post-effective amendment,
                  financial statements required pursuant to this paragraph
                  (a)(4) and other information necessary to ensure that all
                  other information in the prospectus is at least as current as
                  the date of those financial statements. Notwithstanding the
                  foregoing, with respect to registration statements on Form
                  F-3, a post-effective amendment need not be filed to include
                  financial statements and information required by Section
                  10(a)(3) of the Act or Rule 3-19 of this chapter if such
                  financial statements and information are contained in periodic
                  reports filed with or furnished to the Commission by the
                  registrant pursuant to Section 13 or Section 15(d) of the
                  Securities Exchange Act of 1934 that are incorporated by
                  reference in the Form F-3.

         (b)      The undersigned Registrant hereby undertakes that, for
         purposes of determining any liability under the Securities Act of 1933,
         each filing of the Registrant's annual report pursuant to Section 13(a)
         or Section 15(d) of the Securities Exchange Act of 1934 (and, where
         applicable, each filing of an employee benefit plan's annual report
         pursuant to Section 15(d) of the Securities Exchange Act of 1934) that
         is incorporated by reference in the registration statement shall be
         deemed to be a new registration statement relating to the securities
         offered therein, and the offering of such securities at that time shall
         be deemed to be the initial bona fide offering thereof.

         (c)      Insofar as indemnification for liabilities arising under the
         Securities Act of 1933 may be permitted to directors, officers and
         controlling persons of the Registrant pursuant to the foregoing
         provisions, or otherwise, the Registrant has been advised that in the
         opinion of the Securities and Exchange Commission such indemnification
         is against public policy as expressed in the Act and is, therefore,
         unenforceable. In the event that a claim for indemnification against
         such liabilities (other than the payment by the Registrant of expenses
         incurred or paid by a director, officer or controlling person of the
         Registrant in the successful defense of any action, suit or proceeding)
         is asserted by such director, officer or controlling person in
         connection with the securities being registered, the Registrant will,
         unless in the opinion of its counsel the matter has been settled by
         controlling precedent, submit to a court of appropriate jurisdiction
         the question whether such indemnification by it is against public
         policy as expressed in the Act and will be governed by the final
         adjudication of such issue.


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                                   SIGNATURES

      Pursuant to the requirements of the Securities Act of 1933, the Registrant
certifies that it has reasonable grounds to believe that it meets all of the
requirements for filing on Form S-8 and has duly caused this Registration
Statement to be signed on its behalf by the undersigned, thereunto duly
authorized, in the City of Hyannis, Commonwealth of Massachusetts, on this
23rd day of July, 1999.

                                EXCEL SWITCHING CORPORATION

                                By:  /s/ Robert P. Madonna
                                     --------------------------------------
                                     Robert P. Madonna
                                     President, Chief Executive Officer
                                     and Chairman of the Board of Directors

                        POWER OF ATTORNEY AND SIGNATURES

      We, the undersigned officers and directors of Excel Switching Corporation,
hereby severally constitute and appoint Christopher Stavros and Stephen S.
Galliker and each of them, with full power to act without the other, his true
and lawful attorney-in-fact and agent, with full power of substitution and
resubstitution, for him and in his name, place and stead in any and all
capacities (until revoked in writing) to sign all amendments (including
post-effective amendments) to this Registration Statement on Form S-8 of Excel
Switching Corporation, and to file the same, with all exhibits thereto and other
documents in connection therewith, with the Securities and Exchange Commission,
granting unto said attorneys-in-fact and agents, and each of them, full power
and authority to do and perform each and every act and thing requisite and
necessary fully to all intents and purposes as he might or could do in person
thereby ratifying and confirming all that said attorneys-in-fact and agents or
any of them, or their or his substitute, may lawfully do or cause to be done by
virtue hereof.

      Pursuant to the requirements of the Securities Act of 1933, this
Registration Statement has been signed below by the following persons in the
capacities and on the dates indicated.



      SIGNATURE                               TITLE(S)                                       DATE

                                                                                       
/s/ Robert P. Madonna                         President, Chief Executive Officer             July 23, 1999
- ------------------------------------          and Chairman of the Board of Directors
Robert P. Madonna                             (Principal Executive Officer)


/s/ Stephen S. Galliker                       Vice President, Finance and                    July 23, 1999
- ------------------------------------          Administration and Chief Financial Officer
Stephen S. Galliker                           (Principal Financial and Accounting Officer)


/s/ Christopher Stavros                       Director, Vice President, General              July 23, 1999
- ------------------------------------          Counsel and Clerk
Christopher Stavros

/s/ Edward L. Breslow                         Director                                       July 23, 1999
- ------------------------------------
Edward L. Breslow

/s/ John Loughlin                             Director                                       July 23, 1999
- ------------------------------------
John Loughlin





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                                  EXHIBIT INDEX



EXHIBIT NO.       DESCRIPTION

4.1               Restated Articles of Incorporation of the Registrant (filed as
                  Exhibit 3.1 to the Registrant's Registration Statement on Form
                  S-1 (Registration No. 333-35791) and incorporated herein by
                  reference).

4.2               Restated By-Laws of the Registrant (filed as Exhibit 3.2 to
                  the Registrant's Annual Report filed on Form 10-K on
                  March 31, 1999 and incorporated herein by reference).

4.3               Amended and Restated 1997 Stock Option Plan (filed as Exhibit
                  10.1 to the Registration's Annual Report filed on Form 10-K on
                  March 31, 1999 and as approved by the stockholders of the
                  Registrant on May 14, 1999 and incorporated herein by
                  reference).

4.4               Form of Non-Qualified Stock Option Agreement under the
                  Registrant's Amended and Restated 1997 Stock Option Plan
                  (filed herewith).

4.5               Rascom, Inc. 1996 Stock Plan (filed as Exhibit 4.3 to the
                  Registrant's Registration Statement on Form S-8 filed with
                  the Commission on May 24, 1999 and incorporated herein by
                  reference)

5.1               Opinion of Testa, Hurwitz & Thibeault, LLP (filed herewith)

23.1              Consent of Arthur Andersen LLP (filed herewith)

23.2              Consent of Testa, Hurwitz & Thibeault, LLP (included in
                  Exhibit 5.1)

24.1              Power of Attorney (included as part of the signature page to
                  this Registration Statement)