The VS-101 Telephone Interface Module provides eight independent duplex talk channels between handsets. A maximum of three handsets can communicate on each channel.
Each channel has provisions to allow for the connection of external devices. A monitoring port provides an audio output for the connection of a handset or recording device for monitoring of the talk channel. An input port allows a remote device (contact closure or logic gate output) to disable the talk channel. A 2nd input port allows a remote device contact closure or logic gate output) to initiate a tone signal (hurry up tone) over the talk channel that can be heard by both conversing parties. Each channel also has an associated status LED to indicate that the circuit is in use.