Product Detail 3 CO lines, 8 station ports (system or single line), with expansion up to 8 COs and 24 station ports Built-in caller ID card (KX-TA62493-3) for COs with call waiting PC programmable system (on site and remote) 3 voice mail options (APITS, CO based or internal VM card) Direct inward system access with fax detection and 3-level auto attendant/OGM (180 sec, 1 ch) . The "Panasonic KX-TA824 Telephone System with 3 KX-T7731B Telephones" is best product for you. We recommended Panasonic KX-TA824 Telephone System with 3 KX-T7731B Telephones