The ACP Modem for Linux is a software based modem. Support software for the ACP modem is composed of a loadable kernel module and a user level application. Together these components support direct connection to public switched telephone networks (PSTNs) and support selected countries world wide. Refer to Section 6 of this document for the supported country list.
The modem also supports the standard communications port interface (ttySx) and is compatible with the Hayes AT Command Set.
ACP Modem software is continually under development. If you encounter bugs or usability issues, please contact us and we'll work to correct them.
This Linux ACP Modem driver was ported from the Windows NT™ version of the driver available from IBM. Many thanks to Keith Frechette, Charles Ball, and Frank Novak for their technical and support efforts in making this project possible.
This document may be reproduced or distributed in any form without prior permission. Modified versions of this document may be freely distributed, provided that they are clearly identified as such, and this copyright is included intact.
Standard asynchronous COM port interface (NS16550A UART compatible) operation
Bell-103/212A, CCITT-V.21/V.22,V.22bis protocols with data from 300 to 2400 bps
CCITT-V.32 protocols with data rates of 4800, 9600 uncoded, and 9600 bps Trellis coded (Optional)
CCITT-V.32bis protocols with data rates of 4800, 9600, 12000, and 14400 bps (optional)
ITU-T V.34 protocols with data rates from 2400 to 33600 bps.
56K capable modem
Hayes AT Command Set compatibility
DTMF and pulse dialing
Asynchronous error recovery protocol
Error correction via Microcom Network Protocol (MNP) classes 1-4
Error correction via the V.42 error correction standard
MNP class 5 for up to 2x data compression
V.42bis for up to 4x data compression
"Adaptive Rate Negotiation" which provides for "Fallback / Fallforward" as line quality deteriorates or improves
Your modem contains 56K technology. To take advantage of this technology, you must first make sure that your Internet Service Provider (ISP) supports a 56K modem protocol. Significantly higher modem connection speeds, up to 56kbps, require all-digital transmission connections from your ISP to the line card in the central office from which your phone line is connected. The actual connection rate may be limited by the quality of your telephone lines. Telephone line quality may vary from location to location. Current regulations limit maximum trasfer rates to 53K. While your modem contains 56K technology, typical maximum connection rates in the receive direction may be significantly less than 56K. Currently, 56K capability is for the receive direction only. The transmit direction uses V.34 technology.