44023-1297 <90-00058>
P
AGE
5
♦
Amplifier
♦
Distribution circuit
♦
Line output (transmit) transformer (T3)
DROP XMT signals (pins 53 and 51) feed through T4 to the pad.
This pad provides 23 dB of attenuation which prevents
overdriving the mute FET. You can strap the attenuation out in
cases of low line levels (below -5 dBm).
49020 Tone Supply Subassembly off-hook and on-hook tones
connect to pins 38 and 40 respectively. The circuits signaling/
control section operates control FETs for these tones and the
mute. Set the amplifier gain with R4. The output signal splits
between the distribution circuit and the LINE XMT output.
The distribution circuit feeds the 440 CMS Multi-Station Pack-
age at pin 42. The line output feeds through T3 to pins 41 and
47.
S
IGNALING
/C
ONTROL
S
ECTION
The signaling/control section processes incoming calls and
outgoing calls. Refer to Fig. 2.
Incoming Calls
The 44023 processes incoming call signaling in one of two ways:
with a two-wire outside facility or a four-wire E and M trunk.
When an incoming call initiates from a two-wire outside facility,
the ring signal (66 Hz to 16 Hz) applies to the 44023 through
two-wire tip and ring leads (pins 44 and 50) to the OC2 detector.
A loop control strap option determines whether the calling
party or only the called party can terminate the call. A wink or
ground removal on the tip terminates a call. Relay K1 closes the
A-B lead contacts (pins 48 and 54) when the 44023 answers the
call.
When an incoming call initiates from an E and M trunk, the
E Lead ring signal applies to pin 1. A E control strap option
determines whether the calling party or only the called party
can terminate the call. The M lead output (pin 21) switches
when the 44023 answers the call.
The OC2 outputs and the E lead circuit apply through a control
timer to:
♦
A 10 to 80-second no answer disconnect timer.
♦
Through the line seize logic to relay K1, control transistor
Q12, and M lead relay K2.
CONTINUED
. . .
CIRCUIT DESCRIPTION
