EXHIBIT 99 (b)

CERTIFICATION PURSUANT TO
18 U.S.C. SECTION 1350,
AS ADOPTED PURSUANT TO
SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the Annual Report of Interphase Corporation (the Company) on Form 10-K for the year ending December 31, 2002 as filed with the Securities and Exchange Commission on the date hereof (the Report), I Steven P. Kovac, Chief Financial Officer of the Company, certify, pursuant to 18 U.S.C. § 1350, as adopted pursuant to § 906 of the Sarbanes-Oxley Act of 2002, that:

     (1)  The Report fully complies with the requirements of section 13(a) or 15(d) of the Securities Exchange Act of 1934; and

     (2)  The information contained in the Report fairly presents, in all material respects, the financial condition and results of operations of the Company.

/s/ Steven P. Kovac

Steven P. Kovac
Chief Financial Officer
March 24, 2003