5
Circuit Description
General Method of Operation:
This unit provides dial
intercom access provisions to appropriately interface
with the telephone system being used. Two -way
amplifier conditions the speech from the telephone
system Tip and Ring, and provides a low impedance,
low level output to the desired speaker via
conventional telephone wiring, i.e., house cable or
station wire.
Detailed Description:
When accessing the
V-1109RTHF, the telephone system will close the Tip
and Ring to form a loop. Loop sense circuitry then
operates relay and logic circuits and returns dial tone
and lamp battery to the telephone set. The logic
circuit receives dialing information and operates
relays and circuitry to supply splash tone and voice
connection to the station selected. On 1A2 systems,
when the called or any other party goes off-hook on
ICM path, the presence of two resistance ground
cancels or turns off speakers (if inhibit resistors are
wired). "Handsfree mode" can only be restored by
terminating call and redialing station. After paging,
the unit automatically disconnects on release of the
telephone system.
Figure 2
