A device for enabling call forwarding instructions to be given from any telephone in the system or in any connecting system need be connected only to the phone line for which call forwarding service is provided and does not require another phone line to communicate with the device. The device employs a ring detector to detect the short ring that occurs when a call is forwarded and to detect the long ring that occurs when call forwarding is not in effect. Upon the detection of one or more short rings, the device seizes the phone line, transmits a "73" signal that cancels call forwarding, and triggers a timer that starts upon a timing interval of preset duration. If another phone call is received at the device within the preset timing interval and an authorization code is transmitted within that interval, the device enables the call forwarding instructions stored in a recorder to be changed. Thereafter, the device will twice transmit the stored call forwarding instructions to the central station within a two minute period.