We used this phone system until we just out grew it. We had it set up with 5 phone lines. Features: Executone M-64 contains 18 programmable keys, Model 84600 M64 Phone has 4-line, 16-character swivel LCD. M64 Executone digital telephone includes 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. Works with Isoetec Digital System/Executone Integrated Digital System. Location: Bellingham it's NOT ok to contact this poster with services or other commercial interests washington