Features: 18 programmable keys, 4-line, 16-character swivel Liquid Crystal Display (LCD). Full speakerphone for internal and external calls, 3 "soft" keys automatically change functions according to call conditions. Can receive a second internal speakerphone call while on a handset or headset call. System equirements/Compatibility: Works with Isoetec Digital System/Executone Integrated Digital System (IDS™).