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.

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