Universal Digital Loop Transceivers (UDLT)

The MC145422 and MC145426 UDLTs are high–speed data transceivers that provide 80 kbps full–duplex data communication over 26 AWG and larger twisted–pair cable up to two kilometers in distance. Intended primarily for use in digital subscriber voice/data telephone systems, these devices can also be used in remote data acquisition and control systems. These devices utilize a 256 kilobaud modified differential phase shift keying burst modulation technique for transmission to minimize RFI/ EMI and crosstalk. Simultaneous power distribution and duplex data communication can be obtained using a single twisted–pair wire.

The devices employ CMOS technology in order to take advantage of their reliable low–power operation and proven capability for complex analog/digital LSI functions.

? Provides Full–Duplex Synchronous 64 kpbs Voice/Data Channel and Two 8 kbps Signaling Data Channels Over One 26 AWG Wire Pair Up to Two Kilometers

? Compatible with Existing and Evolving Telephone Switch Architectures and Call Signaling Schemes

? Automatic Detection Threshold Adjustment for Optimum Performance Over Varying Signal Attenuations

? Protocol Independent

? Single 5 V Power Supply

? 22–Pin PDIP, 24–Pin SOG Packages

? Application Notes AN943, AN949, AN968, AN946, and AN948

MC145422 Master UDLT

? Pin Controlled Power–Down and Loopback Features

? Signaling and Control I/O Capable of Sharing Common Bus Wiring with Other UDLTs

? Variable Data Clock — 64 kHz to 2.56 MHz

? Pin Controlled Insertion/Extraction of 8 kbps Channel into LSB of 64 kbps Channel for Simultaneous Routing of Voice and Data Through PCM Voice Path of Telephone Switch

MC145426 Slave UDLT

? Compatible with MC145500 Series PCM Codec–Filters

? Pin Controlled Loopback Feature

? Automatic Power–Up/Power–Down Feature

? On–Chip Data Clock Recovery and Generation

? Pin Controlled 500 Hz D3 or CCITT Format PCM Tone Generator for Audible Feedback Applications