T1 Circuit module; for KX-TD1232-4 only.
Allows connection of a 1232 system to a digital T1 trunk; providing up to 24
voice channels. It can support any of these line types: loop start; ground
start; TIE; 2-Way DID; OPX. In twin cabinet systems it must be installed in the
master. When a 187 is installed; you can t have a TD180; TD185; TD284; TD382;
TD384 or TD386 module in either cabinet. The eight original CO line circuits in
the slave cabinet can not be used. The eight CO circuits in the master; when
used with the T1 module; can provide 32 CO lines; as compared to a maximum of 24
lines in a twin system without T1. The TD187 must be connected to the phone
company circuits with a Channel Service Unit ("CSU"); purchased
separately