EST EST3X - Page 144

Chapter 5: Installation
134 EST3X Technical Reference Manual
telephone numbers would have to be busied by incoming calls to jam the
system.
Progressive anti-jamming measures would entail the use of one unlisted
telephone number, or two unlisted numbers for maximum dialer integrity.
• The 3-MODCOM must be connected to the incoming line ahead of all
connected equipment on that line, but just behind the demarcation block. This
puts the control unit telephone connection in series, assuring that all
telephones, answering machines, and FAX machines are disconnected
during dial-out to the CMS. This requirement is necessary so the 3-MODCOM
dialer circuit can seize the line for its exclusive use in the event of an alarm.
• Using a telephone line that is considered essential for conducting business at
the site is not preferred. The dialer must be the first connection in line
because it seizes the line and disconnects all other equipment when making a
call. If connection will be made to a telephone company line that is also used
for normal business purposes, advise the customer that the telephone service
will be disrupted for a few minutes during the connection period.
• If the incoming lines to the protected premises involve a rotary telephone line
arrangement, make the connection to the line having the highest number.
This will create the least interference with business lines.
• In areas where the telephone company requires their own connector block be
installed, it should be wired as per the USOC RJ-31X or RJ-38X
configuration. (The RJ-38X configuration is identical to RJ-31X except for a
jumper between 2 and 7 that is used in some residential applications but is
not used by the 3-MODCOM.)
• When the 3-MODCOM is configured as a two-line dialer module, two
incoming lines must be used and connections must be made to each line.
Installing the 3-MODCOM module
Refer to the 3-MODCOM, 3-MODCOMP Modem Communicator Installation
Sheet (P/N 387476) for installation instructions, wiring, and specifications.
Connecting the 3-MODCOM to telephone company lines
Notes
• For the installation of a system in compliance with NFPA 72, the 3-MODCOM
must be connected to loop-start telephone lines. If the site has ground-start
lines, two separate loop-start lines must be installed for the dialer.