MH89791 Datasheet | Mitel Networks

Features - - - Used with the MH89790B Programmable equalization for different line lengths 6d B loop around circuit TL TL TI Ri RL RL Tx T EIT EA L1 EB EC L2 RCHT RCLT Tx R EIR SW RCHR RCLR ISSUE 4 May 1995 Pin Connections 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Description The MH89791 is a programmable network for use with a PCM 30 line interface, specifically the MH89790B on The ISDN EXPRESS™ Card. The MH89791 contains transmit equalizer and a 6 d B pad, for external loop around, with 120Ω input and output impedances. It is fabricated in thick film hybrid technology and is 2 inches high by 0.5 inches wide. The MH89791 is designed to interface to 22 gauge/.6 mm twisted pair. Figure 1 shows how the MH89791 is connected to the transmit side of a PCM 30 interface. The seven switches control the distance settings of the equalizer. Ti, Ri, TL, and RL are the inputs and outputs of the 6 d B pad. The 4 pole double throw relay connected to the transformer inputs and outputs shows how the transmit signal is switched between the equalizer for normal operation, MH89790B OUTA +12V L1 C2 1: OUTB Ordering Information -40°C to 85°C MH89791 20 Pin SIP Hybrid and the 6d B pad for loop around. Figure 2 shows the circuit description of the MH89791 while Figure 3 shows the switch settings for the Tx equalizer. - 1: :0.5 - - S1 S2 EIT EIR Tx T Tx R EA EB EC SW RCLT RCHT RCLR RCHR Ti Ri TL RL C2 = .47µF L1 = 33 µH - - - - S3 S4 S5 S6 S7 Rx T .8: :1 .8: Rx R - - Figure 1 - Connection Diagram 4-219 EQUALIZER S5 Advance Information 240Ω 3600p F 468Ω 1600p F - - - 6d B Pad Ei T Tip O 60Ω S4 - 60Ω - 60Ω Tip Line - 60Ω 60Ω - - - - 60Ω Tx...