MH88632 Datasheet, PDF (1/18 Pages) Mitel Networks Corporation – Central Office Interface Circuit Preliminary Information

MH88632
®
Central Office Interface Circuit
Preliminary Information
Features
• Loop start and ground start capabilities
• Transformerless 2-4 wire conversion
• Programmable transmit/receive gain with 0dB
defaults
• Programmable input impedance with 600Ω and
900Ω defaults
• Programmable network balance with 600Ω,
900Ω, and AT&T compromise default
• One loop start & two ground start relay drivers
• Line state detection outputs
• Forward loop, reverse loop, ring ground, tip
ground, ringing voltage
• +5V operation
• On-hook audio reception (to accommodate ANI)
Applications
Interface to Central Office for:
• PBX
• Key Telephone System
• Channel bank
• Voice Mail
• Terminal Equipment
• Digital Loop Carrier
ISSUE 5
Ordering Information
MH88632 40 Pin SIL Package
0°C to 70°C
April 1995
Description
The Mitel MH88632 Central Office Trunk Interface
circuit provides a complete audio and signalling link
between audio switching equipment and a central
office. The functions provided by the MH88632
include 2-4 Wire Hybrid conversion, programmable
transmit and receive gains, programmable line
impedance and programmable network balance. The
device is fabricated using thick film hybrid
technology which incorporates various technologies
for optimum circuit design and very high reliability.
XLA
XLB
XLC
XLD
LRC
LRD
BRC
BRD
GRC
GRD
RING TIP
VDD VEE ^AGND
RV FL RL RG TG
Loop
Termination
Loop Relay
Driver
Bias Relay
Driver
Ring Ground
Driver
2-4 Wire Hybrid
Impedance
Matching
Network
Balance
Status
Detection
Receive
Gain
Transmit
Gain
VRLY RGND Z1 Z2 Z600 Z900 NS N1 N2 NATT
Figure 1 - Functional Block Diagram
RX
GRX1
GRX0
TX
GTX1
GTX0
2-235