Exhibit 31.2Rule 13a— 14(a) CERTIFICATION OF CHIEF FINANCIAL OFFICERI, Samuel C. Knoch, certify that:1. I have reviewed this quarterly report on Form 10-Q/A of Tollgrade Communications, Inc. 2. Based on my knowledge, this report does not contain any untrue statement of a material fact or omitto state a material fact necessary to make the statements made, in light of the circumstances underwhich such statements were made, not misleading with respect to the period covered by this report; 3. Based on my knowledge, the financial statements, and other financial information included in thisreport, fairly present in all material respects the financial condition, results of operations andcash flows of the registrant as of, and for, the periods presented in this report; 4. The registrant’s other certifying officer and I are responsible for establishing and maintainingdisclosure controls and procedures (as defined in Exchange Act Rules 13a-15(e) and 15d-15(e)) andinternal controls over financial reporting (as defined in Exchange Act Rules 13a-15(f) and15d-15(f)) for the registrant and have: a) Designed such disclosure controls and procedures, or caused such disclosure controls and proceduresto be designed under our supervision, to ensure that material information relating to theregistrant, including its consolidated subsidiaries, is made known to us by others within thoseentities, particularly during the period in which this report is being prepared; b) Designed such internal control over financial reporting, or caused such internal control overfinancial reporting to be designed under our supervision, to provide reasonable assurance regardingthe reliability of financial reporting and the preparation of financial statements for externalpurposes in accordance with generally accepted accounting principles; c) Evaluated the effectiveness of the registrant’s disclosure controls and procedures and presented inthis report our conclusions about the effectiveness of the disclosure controls and procedures, asof the end of the period covered by this report based on such evaluation; and d) Disclosed in this report any change in the registrant’s internal control over financial reportingthat occurred during the registrant’s most recent fiscal quarter (the registrant’s fourth quarterin the case of an annual report) that has materially affected, or is reasonably likely tomaterially affect, the registrant’s internal control over financial reporting; and 5. The registrant’s other certifying officer and I have disclosed, based on our most recent evaluationof internal control over financial reporting, to the registrant’s auditors and the audit committeeof registrant’s board of directors (or persons performing the equivalent function): a) All significant deficiencies and material weaknesses in the design or operation of internal controlover financial reporting which are reasonably likely to adversely affect the registrant’s abilityto record, process, summarize and report financial information; and b) Any fraud, whether or not material, that involves management or other employees who have asignificant role in the registrant’s internal control over financial reporting.Date: March 2, 2006/s/ Samuel C. Knoch