Exhibit 23.1

            CONSENT OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

We have issued our report  dated  March 3, 2005,  except for Note 3, as to which
the date is March 31, 2005,  accompanying the consolidated  financial statements
and schedule included in the Annual Report of Castelle on Form 10-K for the year
ended December 31, 2004. We hereby consent to the  incorporation by reference of
said report in the previously filed Registration  Statements of Castelle on Form
S-8 (File Nos. 333-75247, 333-21845, and 333-06083).

Grant Thornton LLP
San Francisco, CA
April 13, 2005


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