VOICE (where fitted) This port is used to connect an optional public switched telephone network (PSTN) telephone handset, or any other compatible analog equipment, operating in digital tone multiple frequency (DTMF) mode, by connecting the handset’s plug into this port.
This port is in effect an analog to digital convertor which allows you to use your conventional PSTN telephone on an ISDN line. It is capable of supporting ringing current and call progress tones, and supports analog devices to a maximum ringer equivalence number (REN) of two (United Kingdom). Providing one of the two 64 Kbps ISDN channels is not being used by the unit, then a voice call can be made.
Incoming ISDN traffic carries both a voice and data identifier and depending on the type of transmission, a voice call is automatically directed to the appropriate port connected to the telephone handset.
The VOICE port is terminated with an RJ11 socket. If your telephone equipment uses a different connector jack, you will need to obtain a suitable convertor to connect to the VOICE port. A British Telecom to RJ11
Introduction 1-11
convertor is supplied with UK models fitted with a Voice port.