Exhibit 99.1

   1


                                                                    Exhibit 99.1



                                    AGREEMENT

         Pursuant to Rule 13d-1(f)(1) under the Securities Exchange Act of 1934,
as amended, the undersigned hereby agree that only one statement containing the
information required by Schedule 13G need be filed with respect to the ownership
by each of the undersigned of the shares of Common Stock of Turnstone Systems,
Inc.

         EXECUTED as a sealed instrument this 9th day of February, 2001.



                                         /s/ M. Xxxxxx Xxxxxx
                                         ------------------------------
                                         M. Xxxxxx Xxxxxx


                                         /s/ J. Xxxxxxx Xxxxxx
                                         ------------------------------
                                         J. Xxxxxxx Xxxxxx




                                         The X. X. Xxxxxx and M. D. Xxxxxx Trust
                                         UDT dated January 13, 1995



                                         By: /s/ M. Xxxxxx Xxxxxx
                                            -----------------------------
                                            M. Xxxxxx Xxxxxx
                                            Trustee


                                         By: /s/ J. Xxxxxxx Xxxxxx
                                            -----------------------------
                                            J. Xxxxxxx Xxxxxx
                                            Trustee