MH88400 Datasheet, PDF (1/10 Pages) Mitel Networks Corporation – Line Interface Circuit Preliminary Information

MH88400
®
Line Interface Circuit
Preliminary Information
Features
• FAX and Modem interface
• Suitable for V.29 FAX & V.22 bis Data
• Allows caller identification
• Variants match German, UK, 600Ω & 900Ω
network impedances
• Isolation circuitry conforms to international PTT
requirements
• Transformerless 2-4 Wire conversion
• Loop start operation
• Pulse and DTMF operation
• Accommodates external monitor phone
• Line state detection outputs:
-loop current/ringing outputs
-monitor phone switch hook
• Single +5V operation
Applications
Interface to Central Office for:
• DAA
• Modem
• FAX
• Answering Machine
• Terminal Equipment
ISSUE 1
April 1995
Ordering Information
MH88400-1 14 Pin DIL Package
MH88400-2 14 Pin DIL Package
MH88400-3 14 Pin DIL Package
0°C to 70°C
Description
The Mitel MH88400 Line Interface Circuit provides a
complete audio and signalling link between audio
equipment and central office. The functions provided
by the MH88400 include 2-4 Wire conversion, loop
seizure, external monitor phone switch hook status
and ringing voltage and loop current detection. The
device is fabricated as a thick film hybrid which
incorporates various technologies for optimum circuit
design, high voltage isolation and very high
reliability.
Variants are provided to meet German (-1) and UK
(-3) and general 600Ω (-2) line impedance (see
section on Line Impedances).
Isolation Barrier
TIP
RING
TXIN
TF
RLS
PHS
Active
Termination
Transformer
Isolation
Power
Supply
Opto-
Isolation
Audio
Buffer
Opto-
Isolation
Logic Input
Buffer
VDD
AGND
VR
LC
Audio Input
Buffer
Input
Buffer
Opto-
Isolation
Audio
Buffer
Opto-
Isolation
Ring &Loop
Buffer
VX
RVLC
NETWORK CONNECTIONS
Opto-
Isolation
Switch Hook
Buffer
SHK
USER CONNECTIONS
Figure 1 - Functional Block Diagram
2-11