®
MH88520-1
German Subscriber Line Interface Circuit (SLIC)
Preliminary Information
Features
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Differential to single ended conversion
Transformerless 2-2 wire conversion
Minimum installation space
Off-Hook detection and LED indicator drive
Relay drive output
Battery and ringing feed to line
Logic interface: MUTE, SHK, RRC
Mute of incoming audio
Dial pulse detection
Voltage surge protection
German complex input impedance
MH88520-1
ISSUE 4
April 1995
Ordering Information
20 Pin SIL Package
0°C to 70°C
Description
The Mitel MH88520-1 German 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
MH88520-1 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’ (SIL) package allowing
optimum circuit board packing density and very high
reliability.
Applications
Line Interface for:
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Intercoms
Key Systems
PABX
TIP (A)
RING (B)
RING FEED 1
RING FEED 2
Loop Feed/
Ring Feed
JUNC
Speech Circuit
MUTE
VRLY
SHK
RRD
RRC
RGND
Loop Detection
Relay Drive
Circuit
LED
THRESH ADJ
VBAT AGND
VDD
VEE
Figure 1 - Functional Block Diagram
2-63
MITEL [ MITEL NETWORKS CORPORATION ]
