Abstract: A common control circuit is disclosed for controlling bypassing relays to disconnect telephone line auxiliary circuits from their respective lines preparatory to line testing or for other desired purposes. The control circuit responds to a bypass request signal applied to a line by operating an associated bypassing relay and by activating a timing circuit. The timing circuit and other circuitry cooperate to hold the bypassing relay operated for a time interval sufficient for fulfilling the purpose of the bypass. For serving a bypass request received while another request is being served, the appropriate bypassing relay is operated when the subsequent request is received and the timing circuit is reactivated to insure a sufficient test time for the subsequent request. All operated bypassing relays are held operated until the expiration of a time interval during which no new bypass requests are received.