®
MH88500IN
Hybrid Subscriber Line Interface Circuit (SLIC)
Preliminary Information
Features
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Differential to single ended conversion
No transformers required
Minimum installation space
Off-Hook detection and LED indicator drive
Relay drive output
Battery and ringing feed to line
Logic interface: MUTE, OFHK, RC
Mute of incoming audio
Dial pulse detection
Voltage surge protection
MH88500IN
ISSUE 1
April 1995
Ordering Information
20 Pin SIL Package
0°C to 70°C
Description
The Mitel MH88500IN Subscriber Line Interface
Circuit provides a complete interface between the
telephone line and a speech switch requiring only
single bidirectional switch per crosspoint. The
functions provided by the MH88500IN include
bidirectional differential to single ended conversion
in the speech path, line battery feed, ringing feed
and loop and dial pulse detection. The device is
fabricated as a thick film hybrid in a 20-pin ‘single-in-
line’ package allowing optimum circuit board packing
density.
Applications
Line Interface for:
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PABX
Intercoms
Key Systems
VA
1
V
A2
V
B
V
C1
GND
TIP
RING
RING
FEED
Loop Feed/
Ring Feed
Speech Circuit
JUNCTOR
V
A2
CD
V
B
MUTE
OFHK
RD
RC
RGND
Loop Detection
Relay Drive
Circuit
LED
THRESH ADJ
V
C2
Figure 1 - Functional Block Diagram
2-43
MITEL [ MITEL NETWORKS CORPORATION ]
