3Com 520 - Manual (Page 25)

Introduction 1-11
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
convertor is supplied with UK models fitted with a
Voice port.
Rc.bk : RC01.FRM Page 11 Thursday, July 10, 1997 9:53 AM