Saytay NEW Telephone Phone Lineman Butt Test Tester Tool Cable Set Butt Test Tester Lineman Tool Cable Set with Connectors and Joiner (Blue Ash) FSK/DTMF double standard Caller ID display. This set offers Last number redial, On/Off and hangup buttons, so the lineman can check your telephone line fault. Three kinds of external plug head Easy for the lineman to check your telephone line fault. On/Off and hangup buttons.