CSL DualCom GSM Mk1 Installation Manual page 21

PSTN Line Connection Options
DualCom's PSTN connection requires an analogue telephone line. Where
the analogue telephone line also carries ADSL (Broadband) signals refer to
ADSL later in this section.
Connecting other telecoms equipment IN PARALLEL to the analogue
telephone line used by DualCom can stop the unit sending alarm calls
to an Alarm Receiving Centre. Parallel connection should NOT be used
for DualCom when it is used in a security system.
There are several ways that a DualCom may be connected to a PSTN tel-
ephone line particularly when other equipment needs to share the same tel-
ephone line. Some require that your Telecom Service Provider supplies particu-
lar line features. Some require NVM programming options.
The highest security PSTN line for DualCom (Recommended):
A PSTN line supplied as 'outgoing calls only', i.e. Incoming Ringing Barred,
AND the PSTN line is ex-directory,
AND the PSTN line goes to the DualCom ONLY. Other equipment can be
connected to the DualCom A1 & B1 terminals (i.e. series connection) to make
outgoing calls only. See next page.
The next best security option for a PSTN line (Recommended):
A PSTN line supplied with the '3-way calling' feature,
AND the DualCom NVM is programmed for '3-way calling',
AND the PSTN line goes to the Dualcom ONLY. Other equipment can be
connected to the DualCom A1 & B1 terminals (i.e. series connection) for in-
coming and outgoing calls. See next page.
The 'no security' option ( NOT Recommended ):
The PSTN line is supplied without 'outgoing calls only' or the '3-way calling'
feature. This option can not cancel or 'hold' incoming calls and these will
inhibit DualCom from making a telephone call to the Alarm Receiving Centre.
Parallel Connection ( Do NOT use ):
The DualCom A & B terminals connect to the tel-
ephone line, and other equipment connects directly
to the same telephone line.
This connection option can not cancel or 'hold' in-
coming or outgoing calls and these will inhibit
DualCom from making a telephone call to the ARC.
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