2 - 6 lines ; 4 - 32 extensions (There has 2 CO line ports in ech CO line card; and has 4 extension line ports in each extension line card) Password programming Operator attendant Support caller ID Call transferred and call pick-up 3 way conference (1 CO and 2 extension) Call forwarding and do not disturb Music on holding Call duration restricted OGM recording Flash time option  Outward call option Thunder proof Flexible coding of extension number Auto report extension number Priority access Voice recorder compatible