Advanced hybrid telephone system - up to 24 extensions - The KX-TES824E is initially configured to 3 exchange lines and 8 extensions. With optional cards you can easily expand the capacity up to 8 exchange lines and 24 extensions. The system comes with built-in DISA / Message on busy, Extension Caller ID, Remote Modem and USB Port for PC Programming. Featuring DISA (Direct Inward System Access) which allows outside callers to access any extension without going through an operator. Automatic greeting messages can be recorded by the operator of manager, directing the call to an appropriate department or destination. The system is smart enough to even detect an incoming fax transmission - routing the call automatically to a designated fax extension. Extension Caller ID compatibility displays the incoming caller's phone number or name when used with a Panasonic proprietary display telephone. Up to 20 calls can be logged per extension. The Optional Voice Message Card ensures you will never miss a call when you are not available. You can customize you voice mailbox, by recording your own greetings which will be played when you cannot answer your phone. This system supports the KXT7700 series range of telephones (KXT7735, KXT7730, KXT7720 and KXT7750).