The RS8953B is a High-Bit-Rate Digital Subscriber Line (HDSL) channel unit designed to perform data, clock, and format conversions necessary to construct a Pulse Code Multiplexed (PCM) channel from one, two, or three HDSL channels. The PCM channel consists of transmit and receive data, clock and frame sync signals configured for standard T1 (1544 kbps), standard E1 (2048 kbps), or custom (Nx64 kbps) formats. The PCM channel connects directly to a Bt8370 T1/E1 Controller or similar T1/E1 device Connection to other network/subscriber physical layer devices is supported by the custom PCM frame format. Three identical HDSL channel interfaces consist of serial data and clock connected to a Bt8970 HDSL Transceiver or similar 2B1Q bit pump device. The RS8953SPB contains one HDSL channel interface.

Distinguishing Features
• Supports All HDSL Bit Rates
    – 2 pair T1 standard (784 kbps)
    – 2 pair E1 standard (1168 kbps)
    – 3 pair E1 standard (784 kbps)
    – 1/2/3 pair custom (Nx64 kbps, N=2-36)
• T1/E1 Primary Rate (PCM) Channel
    – Connects to Conexant E1/T1 Framers
    – Framed or unframed mode
    – Sync/Async payload mapping
    – Clock recovery/jitter attenuation
    – PRBS/fixed test patterns
    – BER measurement
• HDSL Channels
    – Connects to Conexant ZipWire Transceivers
    – Three independent serial channels
    – Central, remote, or repeater
    – Overhead (HOH) management
    – Programmable path delays
    – Error performance monitoring
    – Software controlled EOC and IND
    – Auxiliary payload/Z-bit data link
    – Master loop ID and interchange
    – Auto tip/ring reversal
• Programmable Data Routing
    – PCM timeslots – HDSL payload
    – Drop/Insert – HDSL payload
    – Auxiliary – HDSL payload
    – PRBS/Fixed – PCM or HDSL
    – PCM and HDSL loopbacks
• Intel® or Motorola® MPU interface
• CMOS technology, 3.3 V operation
• 68-pin PLCC or 80-pin PQFP

Applications
• Full, Fractional or Multipoint T1/E1
• Single and Multichannel Repeaters
• Voice Pair Gain Systems
• Wireless LAN/PBX
• PCS, Cellular Base Station
• Fiber Access/Distribution
• Loop Carrier, Remote Switches
• Subscriber Line Modem