Filed by Symmetricom, Inc.

Pursuant to Rule 425 under the Securities Act of 1933

Subject Company: Datum, Inc.

Commission File No. 000-06272

Additional Information

Symmetricom and Datum, Inc. will file with the SEC a joint proxy statement/prospectus and other relevant documents concerning the proposed merger transaction whereby Datum will merge into a subsidiary of Symmetricom and become a wholly owned subsidiary of Symmetricom. Investors are urged to read the joint proxy statement/prospectus when it becomes available and any other relevant documents filed with the SEC because they will contain important information. You will be able to obtain the documents free of charge at the website maintained by the SEC at www.sec.gov. In addition, you may obtain documents filed with the SEC by Symmetricom free of charge by requesting them in writing from Symmetricomat or by telephone at 408-433-0910. You may obtain documents filed with the SEC by Datum free of charge by requesting them in writing from Datum or by telephone at 949 598 7500.

Except for the historical information contained herein the attached copies of Powerpoint slides contain forward-looking information within the meaning of Section 27A of the Securities Act of 1933 as amended, and Section 21E of the Securities Exchange Act of 1934 as amended, and are subject to the Safe Harbor created by those sections. These forward-looking statements include, but are not limited to the following: statements as to the expected benefit of the combination of the Symmetricom and Datum, Symmetricom’s expectation that it will close the Datum acquisition, and as a result of that anticipated acquisition it will expand its customer base, acquire new distribution channels, broaden its core competencies and core technologies, better serve customers’ needs for network maintenance, achieve certain vertical integration, and acquire new addressable breakout opportunities and a deeper management team. Forward looking statements also include statements as to the future performance of new products, projections as to future revenue growth, the anticipated benefits of deployment of network access with GoWide, projected industry and Symmetricom milestones for G.shdsl, G.shdsl projected market size, the growth potential for business DSL, and statements that Symmetricom expects to capitalize on their G.dshl product offering to create a leadership position in the broadband market. Symmetricom’s actual results could differ materially from those projected or suggested in these forward-looking statements. Factors that could cause future actual results to differ materially from the results projected in or suggested by such forward-looking statements include, but are not limited to the satisfaction of certain conditions to closing of the proposed acquisition, the ability to close the acquisition, and the ability to integrate Datum and its technology following the acquisition, reduced rates of demand for wireless and wireline telecommunications services and high bandwidth applications, increased competition, timing, cancellation or delay of customer orders, failure of new products to pass interoperability testing and field trials, difficulties in manufacturing products and specifications, customer acceptance of new products, customer delays in qualification of key new products, and the risk factors listed from time-to-time in Symmetricom’s reports filed with the Securities & Exchange Commission, including but not limited to the report on Form 10-K for the year ended June 30th, 2001, and the report on Form 10-Q for the quarter ended March 31, 2002. These forward-looking statements speak only as of the date hereof Symmetricom disclaims any intention or obligation to update or revise any forward-looking statements.

THE FOLLOWING ARE SLIDES PREPARED

WITH RESPECT TO SYMMETRICOM, INC.

AND/OR DATUM, INC. WITH RESPECT TO THE PROPOSED MERGER

OF DATUM, INC. INTO A SUBSIDIARY OF SYMMETRICOM