MH88630

® MH88630 Central Office Interface (LS/GS) Preliminary Information Features Transformerless 2-4 Wire conversion Line state detection outputs: forward current reverse current ring ground tip ground ringing voltage ISSUE 7 April 1995 Ordering Information MH88630 40-Pin DIL Package 0° C to 70° C Description The Mitel MH88630 Central Office Trunk Interface circuit provides a complete audio and signalling link between an audio switching equipment and a central office. The loop seize circuitry is controlled by an external input to provide either a loop start or ground start termination. The device is fabricated using thick film hybrid technology to achieve high density circuit design. Programmable audio transmit and receive gain Loop start or ground start termination Selectable 600 Ω or AT&T compromise balance network Applications PBX Interface to Central Office Channel bank Intercom Key system RG FC RV RC TG LPGND RINGND VCC+ VCC- AGND T R Signal Detection Circuitry Ring Ground Relay Driver 1 Relay Driver 2 VTR+ VTRRXINRXIN+ Network Balance Active Termination Audio Section Circuitry (2 - 4 Wire) RC1 RD1 RGND CD RD2 RC2 NETBAL GSX VX VR GSR QB QE XA XB XC VDD VEE RXOUT TXIN+ TXIN- Figure 1 - Functional Block Diagram 2-215 MH88630 IC T R IC IC LPGND RINGND VTR+ QE QB VTRXA XB XC RGND RC1 RD1 CD RD2 RC2 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 40 39 38 37 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 RG FC RV RC TG VDD VEE AGN...