SYSTEM OVERVIEW
STU2071 (UIC) provides two transparent 64 kbit/s B channels, a transparent 16 kbit/s D channel, a transparent 1 kbit/s service channel and a 1 kbit/s maintenance channel for loop and error messages on subscriber lines. UIC enables full duplex continuous data transmission via the standard twisted pair telephone cable. Adaptive Echo cancellation is used to restore the received data. An equalizer, done with an adaptive filter, restores the data which are distorted by the transmission line.

■ 4B3T TWO-WIRE U INTERFACE CIRCUIT FOR LT AND NT APPLICATION
■ 120 kbaud LINE SYMBOL RATE (120 SYMBOLS PER FRAME)
■ SCRAMBLER AND DESCRAMBLER ACCORDING TO CCITT REC V.29
■ BARKER CODE (11 SYMBOLS) SYNCHRONIZATION WORD
■ UNSCRAMBLED 1 KBIT/S HOUSEKEEPING CHANNEL
■ ADAPTIVE ECHO CANCELLATION WITH TRANSVERSAL FILTERING
■ ADAPTIVE DECISION FEEDBACK EQUALIZATION
■ AUTOMATIC GAIN CONTROL
■ PDM AD CONVERTER
■ AUTOMATIC ACTIVATION AND DEACTIVATION WITH POLARITY ADAPTION
■ AUTOMATIC CODE VIOLATION DETECTION
■ POWER FEED UNIT CONTROL
■ ADVANCED CL3 1.5µm CMOS PROCESS
■ 28 PIN DUAL-IN-LINE PLASTIC PACKAGE
■ V* DIGITAL INTERFACE