Introduction
The DSP1648C, host-accelerated modem chip is an exciting new upgrade to Agere Systems Inc. line of host-based controller modems. The DSP1648C upgrades the technologies found in the DSP1648 V.90 modem solution to the new ITU-T recommendations V.92 and V.44 communication industry standards. V.92 and V.44 have four innovative features, designed to improve modem performance in the internet environment. The new features are as follows:

■ Modem fast connect: faster start-up times.
■ Modem on hold†: switch between modem and an incoming phone call without losing the data connection.
■ PCM upstream: send data to central site at rates approaching 48 kbits/s.
■ Data compression enhancement focused on todays internet traffic.

Features
■ Two chip 3.3 V PCI modem solution with 5 V tolerant buffers
■ Data mode capabilities:
   — ITU-T V.92*: 56000 bits/s—28000 bits/s
   — ITU-T V.90*: 56000 bits/s—28000 bits/s
   — ITU-T V.34: 33600 bits/s—2400 bits/s
   — V.32bis, and fallbacks
   — V.42 and MNP ™ error correction (LAPM)
   — V.44, V.42bis and MNP Class 5 data compression
■ FAX mode capabilities:
   — ITU-T V.17, V.29, V.27ter, and V.21 Ch 2
   — ITU-T T.31 Class 1 FAX
■ Compatible with transformer-based and silicon DAA circuits:
   — High-precision sigma-delta codec (CSP1034C)
   — Line-powered silicon DAA (CSP1035A)
■ Enhanced voice features:
   — Full-duplex speakerphone (requires CSP1027 audio codec)
   — Telephone answering machine (TAM)
   — Caller identification (caller-ID)
■ V.80 video-ready interface
■ Bit I/Os to support domestic and international DAAs
■ Low power consumption
■ Flexible power management modes
■ Operating system support:
   — Windows ® 95, 98, 2000, Windows NT ® 4.0, Windows ME, and Windows XP
   — Linux ®
   — PC 2001 compliant