20 double-assignable, programmable keys with dual LED and 160x320 graphic LCD display, max. 6 extension modules cascadable, thus max. 120 programmable keys with dual LED and LCD display. Supported functions: busy lamp field, intercom, direct pickup, group pickup, conference, hold, transfer, group listening, call return, voicemail. A power supply unit must be used from the 2nd keypad. for T46G, T48G