The TIF-4000 is a frame of up to 12 digital telephone interface cards (TIF-4000 front card), with a redundant power supply. The TIF-4000 is designed to be compatible with ADAM, ADAM-M, and Zeus intercom systems. It provides bidirectional communication between the intercom matrix and an analog telephone line. It allows the phone to access all crosspoints of the matrix, as well as dynamic party lines, IFB circuits, and other forms of communications. The 4 RU high, rack-mountable TIF-4000 provides a transparent link to the telephone system enabling full dial-out capability from any designated keypanel with keypad. The TIF-4000 has full dial-in capability giving the caller a keypanel on the system via commands from the DTMF pad on their telephone.