EXHIBIT 7.7

           AMENDMENT TO 1993 NON-EMPLOYEE DIRECTOR STOCK OPTION PLAN


                                 AMENDMENT NO. 2
                                       TO
                  1993 NON-EMPLOYEE DIRECTOR STOCK OPTION PLAN
                                       OF
                    CELLULAR TECHNICAL SERVICES COMPANY, INC.
                        (Effective as of April 22, 1999)

         Paragraph 4 of the Plan is hereby amended to read as follows:

"4.      OPTION GRANTS

         Each individual who first becomes an Outside Director after the
effective date of the Plan shall be granted on the date he or she first becomes
an Outside Director an option to purchase 5,000 shares of Common Stock. In
addition, on January 2 of each year beginning with January 2, 1994, each Outside
Director then in office shall be granted an option to purchase an additional
3,000 shares of Common Stock. Furthermore, subject to the express provisions of
the Plan, the Board also shall have the authority, in its sole discretion, to
determine: the Outside Directors who shall be granted options in addition to the
option grants described above; the times when such additional options shall be
granted; the number of shares of Common Stock to be subject to each such
additional option; whether and under what conditions to accelerate the date of
exercise of any such additional option; whether to restrict the sale or other
disposition of the shares of Common Stock acquired upon the exercise of such an
option and, if so, whether to waive any such restriction; whether to subject the
exercise of all or any portion of an option to the fulfillment of contingencies
as specified in the contract referred to in Paragraph 13 hereof and to determine
whether such contingencies have been met; and, with the consent of the optionee,
to cancel or modify an option, provided, that the modified provision is
permitted to be included in an option granted under the Plan on the date of the
modification."