WEISMAN CELLER SPETT & MODLIN, P.C.           Exhibit 5.1

                                 445 PARK AVENUE

                              NEW YORK, N. Y. 10022



                                 (212) 371-5400

                                                       TELECOPIER (212) 371-5407





                                        April 7, 2005



General DataComm Industries, Inc.
6 Rubber Avenue
Naugatuck, CT 06770

      Re:   General DataComm Industries, Inc.
            2003 Stock and Bonus Plan
            -------------------------

Gentlemen:

      We have assisted in the preparation of a Registration Statement on Form
S-8 (the "Registration Statement") to be filed with the Securities and Exchange
Commission (the "Commission") under the Securities Act of 1933, as amended (the
"Securities Act"), relating to an aggregate of 918,536 shares of Common Stock,
$0.01 par value per share (the "Shares"), of General DataComm Industries, Inc.,
a Delaware corporation (the "Company"), issuable under the Company's 2003 Stock
and bonus Plan (the "Plan").

      We have examined the Certificate of Incorporation and By-Laws of the
Company, each as amended and restated to date, and originals, or copies
certified to our satisfaction, of all pertinent records of the meetings of the
directors and stockholders of the Company, the Registration Statement and such
other documents relating to the Company as we have deemed material for the
purposes of this opinion.

      In our examination of the foregoing documents, we have assumed the
genuineness of all signatures, the authenticity of all documents submitted to us
as originals, the conformity to original documents submitted to us as certified,
photostatic or other copies, the authenticity of the originals of any such
documents and the legal competence of all signatories to such documents.

      Based on the foregoing, we are of the opinion that the Shares have been
duly authorized for issuance and, when the Shares are issued in accordance with
the terms and conditions of the Plan, the Shares will be validly issued, fully
paid and nonassessable.

                                                                               9


      We hereby consent to the filing of this opinion with the Commission in
connection with the Registration Statement in accordance with the requirements
of Item 601(b)(5) of the Regulation S-K under the Securities Act. In giving such
consent, we do not hereby admit that we are in the category of persons whose
consent is required under Section 7 of the Securities Act or the rules and
regulations of the Commission.

                                         Very truly yours,


                                         /s/ WEISMAN CELLER SPETT & MODLIN, P.C.
                                         ---------------------------------------
                                         WEISMAN CELLER SPETT & MODLIN, P.C.

                                                                              10