1

                                                                     Exhibit 5.1


                                        February 12, 2001

Tollgrade Communications, Inc.
493 Nixon Road
Cheswick, PA  15024


      Re:  Registration Statement on Form S-8 for Tollgrade Communications, Inc.
           1998 Employee Incentive Compensation Plan
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Gentlemen:

         We have acted as counsel to Tollgrade Communications, Inc., a
Pennsylvania corporation (the "Company"), in connection with the above-captioned
Registration Statement (the "Registration Statement") relating to 200,000 shares
of Common Stock, par value $.20 per share, of the Company (the "Common Stock")
which may be purchased by certain employees of the Company pursuant to stock
options granted under the 1998 Employee Incentive Compensation Plan (the
"Plan"). The Plan provides that either authorized but unissued or treasury
shares of Common Stock may be issued upon the exercise of stock options granted
under the Plan. In rendering our opinion below, we have assumed that any
previously issued shares reacquired by the Company and delivered under the
Options will have been duly authorized, validly issued and fully paid at the
time of their original issuance.

         In connection with this opinion, we have examined, among other things:

                  (1) the Articles of Incorporation of the Company, as amended
         to date;

                  (2) actions taken by the Board of Directors of the Company on
         December 14, 2000, authorizing the issuance of up to an additional
         200,000 shares of Common Stock under the Plan and reserving 200,000
         shares of Common Stock for such purpose; and

                  (3)    the Plan as currently in effect.

         Based upon the foregoing and upon an examination of such other
documents, corporate proceedings, statutes, decisions and questions of law as we
considered necessary in order to enable us to furnish this opinion, and subject
to the assumption set forth above, we are pleased to advise you that in our
opinion the 200,000 shares of Common Stock being registered and which may be
issued by the Company pursuant to the provisions of the Plan have been duly
authorized, and upon such issuance such shares will, when sold, be validly
issued, fully paid and nonassessable.

         In rendering the foregoing opinion, we have not examined the laws of
any jurisdiction other than the laws of the Commonwealth of Pennsylvania and the
federal laws of the United States of America and the foregoing opinion is
limited to such laws.

         We hereby consent to the filing of this opinion as an Exhibit to the
Registration Statement and to the use of our name in the Prospectus under the
caption "Legal Opinion."


                                       Yours truly,

                                       /s/ REED SMITH LLP

                                       REED SMITH LLP
PDG:JGA:clj