Scalable to 3 expansion modules per phone Power direct from phone No external power adapter required Programmable features Line, speed-dial, BLF, BLA, SCA, DND 536M expansion module 36-keys with LED Paper strip labeling Supported on 55i, 57i, 57i CT 560M expansion module 60-keys with LED (3 pages of 20) Self-labeling LCD backlit display Supported on 57i, 57i CT Aastra 560M M675i , A1760-0000-10-55