MH88422 Datasheet, PDF (1/12 Pages) Mitel Networks Corporation – Line Interface Circuit Preliminary Information

MH88422
®
Line Interface Circuit
Preliminary Information
Features
• FAX and Modem interface (V29/V22 bis)
• Variants match German, UK & 600Ω network
impedances
• Provides reinforced barrier 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
• Single +5V operation, low idle power (5mW)
• Full Duplex
• Suitable for power down applications
Applications
Interface to Central Office for:
• DAA
• Modem
• FAX
• Answering Machine
• Terminal Equipment
ISSUE 5
Ordering Information
April 1995
MH88422-1 14 Pin DIL Package
MH88422-2 14 Pin DIL Package
MH88422-3 14 Pin DIL Package
Surface Mount Options are available by adding the
Suffix “S”
Description
The Mitel MH88422 Line Interface Circuit provides a
complete audio and signalling link between audio
equipment and central office. The functions provided
by the MH88422 include 2-4 Wire conversion, loop
seizure, ring voltage and loop current detection. The
device is fabricated as 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) line impedance (see section on Line
Impedances), as well as a 600Ω variants (-2).
Isolation Barrier
TIP
RING
Active
Termination
TXIN
TF
RLS
Audio Input
Buffer
Input
Buffer
NETWORK CONNECTIONS
Power
Supply
Opto-
Isolation
Logic Input
Buffer
Opto-
Isolation
Audio
Buffer
Opto-
Isolation
Audio
Buffer
Opto-
Isolation
Ring & Loop
Buffer
Transhybrid
Loss
Cancellation
Circuit
USER CONNECTIONS
VDD
AGND
LC
VR
VX
RVLC
Figure 1 - Functional Block Diagram
2-21