®
MH88632B
Central Office Interface Circuit
Preliminary Information
Features
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Supports Loop Start and Ground Start protocols
2-4 Wire conversion
Programmable Input Impedance, Network
Balance Impedance and gains
Three relay drivers
Line state detection outputs
15mA operation allowing long line length
capability
On-hook reception for Caller Line Identification
Meets FCC Part 68 Leakage Current
Requirements
ISSUE 3
September 1997
Ordering Information
MH88632B 40 Pin SIL Package
MH88632BT 40 Pin 90˚ Package
0°C to 70°C
Description
The Mitel MH88632B Central Office Interface Circuit
provides a complete analog and signalling link
between audio switching equipment and a subscriber
line. The device is available in a single in line
package for high packing densities or in a 90˚
package for reduced card clearance.
The device is fabricated using thick film hybrid
technology for optimum circuit design and very high
reliability.
Applications
Interface to Central Office telephone line for
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PBX
Key Telephone System
Terminal Equipment
Digital Loop Carrier
Wireless Local Loop
RV
FL
RL RG TG
VCC
VEE
AGND
GRD GRC BRD BRC LRD LRC
Status
Detection
VRLY
Relay Driver Circuit
RGND
RING
Line
Termination
2-4 Wire
Hybrid
Receive
Gain
Dummy
Ringer
RX
GRX1
GRX0
Transmit
Gain
TIP
Network
Balance
TX
GTX1
GTX0
Impedance
Matching
XLA XLB XLC XLD
Z1 Z2 Z600 Z900
NS N1 N2 NATT
Figure 1 - Functional Block Diagram
2-239
MITEL [ MITEL NETWORKS CORPORATION ]
