GENERAL DESCRIPTION
The ADSL modem chip set with ATM interface provides all the active functions required to build a complete ATM-based ADSL modem from line interface to ATM UTOPIA bus. The chip set employs Discrete MultiTone modulation as specified in ANSI T1.413.
The chip set operates at CPE end of the loop (ATU-R mode). Reed-Solomon forward error correction plus Trellis coding with or without interleaving in internal interleaving RAM provides maximum noise immunity (see Figure 3).
Interleaving is optional and can be used simultaneously on a slow channel (e.g., for data or control info) while a fast channel (e.g., video) operates without interleaving. ICs include rate adaptation capabilities during show time. In transmit direction the chip set allows to select an attenuation of the signal in case of short loops or large echo (politeness). In receive direction the chip set can optionally control an external multiplexer to select an external attenuation of the signal in case of short loops, and provide a 2-bit output external gain control.

■ COMPLETE CHIP SET FOR ADSL CPE MODEM
■ COMPLIANCE WITH ANSI T1.413 ISSUE
1 & ISSUE 2
■ COMPLIANCE WITH G.992.1 (FULL RATE) & G.992.2 (G. LITE)
■ IMPLEMENTS DISCRETE MULTITONE (DMT) MODULATION AND DEMODULA TION ON CPE SIDE
■ DATA RATES UP TO 8Mbps DOWNSTREAM AND TO 1Mbps UPSTREAM WITH 32Kbps GRANULARITY
■ BUILT-IN ATM TRANSPORT
■ SUPPORT ADAPTIVE RATE MODE IN 32Mbps INCREMENTS
■ 255/128 CARRIERS WITH 4.3125KHz SPACING
■ DEDICATED SOFTWARE DRIVER AVAILABLE
■ PROCESSOR INDEPENDENT C++ SOURCE COMPILATION
■ FREQUENCY DIVISION MULTIPLEXING (FDM) FOR HIGH ROBUSTNESS IN PRESENCE OF CROSSTALK
■ REED-SOLOMON FORWARD ERROR CORRECTION
■ TRELLIS CODER AND DECODER
■ PROGRAMMABLE SIMULTANEOUS SUPPORT OF INTERLEAVED AND NON-INTERLEAVED CHANNELS (DUAL LATENCY)
■ FULL, REDUCED AND MINIMAL ATM OVERHEAD FRAMING MODES
■ BIT STREAM MODE CAPABLITY FOR STM TRANSPORT
■ DIRECT CONNECTION TO ATM SYSTEMS VIA UTOPIA INTERFACE (LEVEL 1 OR 2)
■ MICROCONTROLLER INTERFACE WITH 16 BITS MULTIPLEXED ADDRESS/DATA BUS
■ LOW POWER TECHNOLOGY: 1.3w TOTAL
■ SINGLE 3.3V POWER SUPPLY
■ 0 TO +70°C OPERATING TEMPERATURE RANGE

APPLICATIONS
■ HIGH SPEED INTERNET ACCESS
■ REMOTE ACCESS TO CORPORATE NET WORK FOR TELECOMMUTERS AND BRANCH OFFICES
■ VIDEO-ON-DEMAND OVER TWISTED PAIR
■ CPE ADSL MODEMS, AND ROUTERS
■ ADSL PC NICs
■ G. LITE CPE SPLITTERLESS APPLICATIONS