®
MH88631
Central Office Interface (LS/GS)
Preliminary Information
Features
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Transformerless 2-4 wire conversion
Line state detection outputs
- forward current
- reverse current
- ring ground
- tip ground
- ringing voltage
Programmable audio transmit and receive gain
Loop start or ground start termination
Selectable 600Ω or AT&T compromise balance
network
-1 version: 20Hz Ringing Voltage
-2 version: 50Hz Ringing Voltage
ISSUE 4
April 1995
Ordering Information
MH88631-1
MH88631-2
40 Pin SIL Package
40 Pin SIL Package
0°C to 70°C
Description
The Mitel MH88631-1, 2 Central Office Trunk
Interface circuit provides a complete audio and
signalling link between audio switching equipment
and a central office. The loop seize circuitry is
controlled by an external input to provide either a
loop start of ground start termination. The device is
fabricated using thick film ceramic technology to
achieve high density circuit design.
Applications
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PBX
Channel bank
Intercom
Key System
RG FC RV RC TG
LPGND RINGND
VCC+ VCC- AGND
T
R
Signal Detection
Circuitry
Ring
Ground
Relay
Driver 1
Relay
Driver 2
RC1
RD1
RGND
CD
RD2
RC2
NETBAL
Network
Balance
VTR+
VTR-
RXIN-
RXIN+
Active
Termination
Audio Section
Circuitry
(2-4 Wire)
GSX
VX
VR
GSR
QB QE XA XB XC
VDD VEE
RXOUT
TXIN+ TXIN-
Figure 1 - Functional Block Diagram
2-225
MITEL [ MITEL NETWORKS CORPORATION ]
