1


                                                                   Exhibit 4.1.5




Number                                                       Shares
------                                                       ------


                             PICTURETEL CORPORATION

                    Series B Preference Stock, $.01 par value

       SEE REVERSE SIDE FOR RESTRICTIONS ON TRANSFER AND CLASSES OF STOCK


This certifies that ______________________ is the owner of _______________
shares, fully paid and nonassessable, of the Series B Preference Stock of
PictureTel Corporation, a Delaware corporation, transferable only on the books
of the corporation by the holder thereof in person or by attorney upon surrender
of this certificate properly endorsed.

This certificate and the shares represented hereby are subject to the laws of
the State of Delaware and to the Certificate of Incorporation and the By-laws of
the corporation, in each case as from time to time amended.

IN WITNESS WHEREOF, PictureTel Corporation has caused this certificate to be
signed by its duly authorized officers and its corporate seal to be hereto
affixed this day    of         , 2000.


-------------------------------                 -------------------------------
President or Vice President                     Treasurer or Assistant Treasurer

   2


                            RESTRICTIONS ON TRANSFER

         The shares of stock represented by this certificate have not been
registered under the Securities Act of 1933, as amended, and may not be sold,
assigned, pledged or otherwise transferred in the absence of an effective
registration statement under said Act covering the transfer or an opinion of
counsel satisfactory to the issuer that registration under said Act is not
required.

         The powers, designations, preferences and rights and the
qualifications, limitations or restrictions thereof of each class of stock or
series of any class are set forth in the Restated Certificate of Incorporation,
as amended. The corporation will furnish a copy of the Restated Certificate of
Incorporation, as amended, to the holder of this certificate without charge upon
request.

         These securities are subject to the terms and provisions of a Stock
Purchase and Investor Rights Agreement dated as of July 13, 2000 between the
holder of this Certificate of Series B Preference Stock, the other Investors
party thereto and PictureTel Corporation. Copies of such Agreement may be
obtained without charge upon written request to the secretary of the Company.

                                   ASSIGNMENT


         For value received, ___________________________________ hereby sell,
assign and transfer to __________________________ shares of the Capital Stock
represented by this Certificate, and do hereby irrevocably constitute and
appoint ______________________________, Attorney to transfer such stock on the
books of _________________________________ with full power of substitution in
the premises.

         Dated _________________, 20__


                           ----------------------------------------------------
                           Signature of registered owner corresponding exactly
                           to the name of such owner as written on the face of
                           this certificate


--------------------------
Witness