EXHIBIT 1 JOINT FILING 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 13D needs to be filed with...

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                                                                       EXHIBIT 1

                             JOINT FILING 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 13D needs to be filed with respect to the
ownership by each of the undersigned of shares of stock of Alarmguard Holdings,
Inc.

     EXECUTED this 11th day of March, 1998.

                                 CANAAN EQUITY L.P.

                                 By:   Canaan Equity Partners LLC
                                       Its General Partner

                                     By:        *
                                    ----------------------------
                                        Member/Manager

                                    CANAAN EQUITY PARTNERS LLC

                                    By:         *
                                    ----------------------------
                                    Member/Manager

                                     *
                                    ----------------------------
                                    Xxxxx X. Xxxx

                                     *
                                    ----------------------------
                                    Xxxxxxx X. Xxxxx

                                     *
                                    ----------------------------
                                    Xxxxxx Xxxxx

                                     *
                                    ----------------------------
                                    Xxxxxxx Xxxxxxxxxx

                                     *
                                    ----------------------------
                                    Xxxxxx X. Xxxxxxxxxx

                                     *
                                    ----------------------------
                                    Xxx X. Xxxxx

                                     *
                                    ----------------------------
                                    Xxxx X. Xxxxx

*/s/ Xxx X. Xxxxx
 ----------------
 Xxx X. Xxxxx
 As Attorney-in-Fact

     This Schedule 13D was executed by Xxx X. Xxxxx pursuant to the Power of
Attorney, which is attached hereto as Exhibit 2.