Description

The Lucent Technologies Microelectronics Group T7264 U-Interface 2B1Q Transceiver integrated circuit provides full-duplex, basic-rate (2B+D) integrated services digital network (ISDN) communications on a 2-wire digital subscriber loop at either the LT or NT and conforms to the ANSI North American Standard T1.601-1992. The single +5 V CMOS device is packaged in a 44-pin plastic leaded chip carrier (PLCC).

Features

■ U-interface 2B1Q transceiver
— Range over 18 kft on 26 AWG
— ISDN basic-rate 2B+D
— Full-duplex, 2-wire operation
— 2B1Q four-level line code
— Conforms to ANSI North American Standard T1.601-1992
— Supports NT quiet mode and insertion loss test mode for maintenance
■ K2 interface
— 2B+D data
— 512 kbits/s TDM interface
— Frame and superframe markers
— Embedded operations channel (eoc)
— U-interface M bits and crc results
— Device control and status
■ Other
— Single +5 V (±5%) supply
— –40 °C to +85 °C
— 44-pin PLCC
■ Power consumption
— Operating 275 mW typical
— Idle mode 30 mW typical
■ Analog front end
— On-chip line driver for 2.5 V pulses
— On-chip balance network
— Sigma-delta A/D converter
— Internal 15.36 MHz crystal oscillator
— Supports 15.36 MHz external clock input
■ Digital signal processor
— Digital timing recovery (pull range ±250 ppm)
— Echo cancellation (linear and nonlinear)
— Accommodates distortion from bridged taps
— Scrambling/descrambling
— crc calculations
— Selectable LT or NT operation
— Start-up sequencing with timers
— Activation/deactivation support
— Cold start in 3.5 seconds (typical)
— Warm start in 200 ms (typical)
— U-frame formatting and decoding