NOTICE OF GUARANTEED DELIVERY
TENDER OF SHARES OF COMMON STOCK
(INCLUDING THE ASSOCIATED PREFERRED STOCK PURCHASE RIGHTS)
PREMISYS COMMUNICATIONS, INC.
As set forth in Section 3 of the Offer to Purchase described below, this Notice of Guaranteed Delivery, or one
substantially equivalent hereto, must be used to accept the Offer (as defined below) if certificates evidencing
Shares (as defined below) are not immediately available, or the certificates for Shares and all other required
documents cannot be delivered to ChaseMellon Shareholder Services, L.L.C. (the "Depositary") prior to the
Expiration Date (as defined in
Section 1 of the Offer to Purchase), or if the procedure for delivery by book-entry transfer cannot be completed
on a timely basis. This instrument may be delivered by hand or transmitted by facsimile transmission or mailed to
the Depositary. See Section 3 of the Offer to Purchase.
THE DEPOSITARY FOR THE OFFER IS:
CHASEMELLON SHAREHOLDER SERVICES, L.L.C.
DELIVERY OF THIS NOTICE OF GUARANTEED DELIVERY TO AN ADDRESS OTHER THAN AS
SET FORTH ABOVE OR TRANSMISSION OF INSTRUCTIONS VIA FACSIMILE TRANSMISSION
OTHER THAN AS SET FORTH ABOVE WILL NOT CONSTITUTE A VALID DELIVERY.
DELIVERIES TO THE COMPANY WILL NOT BE FORWARDED TO THE DEPOSITARY AND
THEREFORE WILL NOT CONSTITUTE VALID DELIVERY. DELIVERIES TO THE BOOK-ENTRY
TRANSFER FACILITY WILL NOT CONSTITUTE VALID DELIVERY TO THE DEPOSITARY.
This form is not to be used to guarantee signatures. If a signature on a Letter of Transmittal is required to be
guaranteed by an "Eligible Institution" (as defined in the Offer to Purchase) under the instructions thereto, such
signature guarantee must appear in the applicable space provided in the signature box on the Letter of
The Eligible Institution that completes this form must communicate the guarantee to the Depositary and must
deliver the Letter of Transmittal or an Agent's Message (as defined in Section 3 of the Offer to Purchase) and