1.4 Unit Description; Transmit Voice Path - GE JungleMUX 86445-31 Technical Practice And Installation Manual

1.4 UNIT DESCRIPTION

The 86445-31 FXS unit contains a main assembly board (087-86445-03) and
subassembly board (087-86445-04). The main board consists of a Subscriber
Line Interface Circuit (SLIC) which provides battery feed with subscriber loop
current limiting, overvoltage protection, ring relay driver, supervisory signaling,
and hybrid functions.
adjustment, transmit and receive filtering, hybrid balancing and µ-law PCM
encoding and decoding. A Programmable Logic Gate Array (PLGA) generates
timing signals for processing digital PCM and signaling information from a single
channel into a JVT format. A micro-controller controls and monitors various unit
parameters.
The subassembly board contains the DC-to-DC converter (talk battery) and
ringing generator necessary for telephone operation.
The 86445-31 FXS unit is capable of a local analog loopback that ignores the
local input signal and loops back the far-end receive signal to the remote end.
All user connections are made to the 86445-91 Interconnect Paddleboard. Tip
and Ring connections as well as external Ringing Generator connections and
external Battery Supply connections are provided on one screw type terminal
block. All pinout arrangements are provided in the Installation portion of the
manual.
A simplified Block Diagram has been included at the end of this section and can
be used for reference for the following signal paths analysis, however the user
should refer to schematics EAS-86445-31 for complete circuit descriptions.

Transmit Voice Path

The analog voice signal (at -14.0 to +6.0 dBm level) is sent from the T, R
balanced input at the Paddleboard TB1(1,2) to the back connector J1(A3,A4).
The signal is sent via bantam jack J5 to the Subscriber Line Interface Circuit
(SLIC) U14(22,24) which acts as the 2W to 4W hybrid and as a summing
amplifier to reject Tip and Ring common signals. The signal output from U14(32)
is a function of the differential voltage appearing across resistors R27 and R29.
Copyright  GE Multilin Inc. 2002
A PCM CODEC filter performs input and output level
342-86400-445PS
Issue 4.0
October 2006
Page 17