44443-1098 <90-00059>
P
AGE
11
OPERATION
T
here are no specific operating instructions for the 44443-00
and 44443-01 Term Sets. The module starts operation when
signal is applied.
4-Wire RCV and XMT Line Attenuation
Attenuation of the 4-wire RCV and XMT lines is adjusted by the
DIP switches on the front panel. The 4-wire RCV and XMT ports
of the Term Set are designed to match a 600 ohm line. Attenua-
tion from 0 to 31.875 dB is provided in 0.125 steps.
Front Panel Test Jacks
Four jacks are located on the front panel. Two jacks are provided
for the 2-wire port:
♦
A normal-through (2W IN) interrupts the 2-wire line, allow-
ing access to the Term Set input.
♦
A monitor jack (2W MON) bridges the 2-wire line.
The RCV and XMT ports have normal-through jacks:
♦
The 4-wire RCV jack interrupts the receive line and connects
to the input of the Term Set.
♦
The 4-wire XMT jack interrupts the transmit line and con-
nects to the output of the Term Set.
Echo Suppression Override / Idle Line Termination
Applications
The 44443-01 features a relay activated echo suppression branch
across the 4-wire XMT port. This circuit is used to override echo
suppression when a dial tone has control of the off-net applica-
tions with the 440 Communications Management System. When
activated, relay K1 places a 50 ohm load across the 4-wire XMT
line, reducing the dial tone level. This allows the DTMF tones to
take control of the echo suppression and, by breaking the dial
tone, be received at the central office.
NOTE
: The ILT bypass strap must be installed to prevent line
interruption.
The -01 also includes an Idle Line Termination (ILT) branch
circuit that can be strapped into the 4-wire XMT line when the
echo suppression circuit is not required. Applications of the ILT
branch to the 4-wire XMT line occurs when the K1 relay is
released (not energized). Then the 4-wire XMT line is discon-
nected from the Term Set and the 4-wire XMT port is termi-
nated in 600 ohms.
NOTE
: The ILT bypass strap should not be used in this application.
