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Introduction 1-5
x2 56-kbps Connectivity
If you have enabled x2, your Courier can connect at speeds up to
56 kbps. While line conditions may not always allow for 56 kbps
connections, the new Courier software allows you to achieve the fastest
analog speeds available.
Adaptive Speed Leveling to Adjust to Line Conditions
Adaptive Speed Leveling® (ASL) allows your Courier to monitor line
conditions while connected, and fall back to the next lower speed if
conditions are poor. Couriers also detect improved line conditions and
shift upward to the next higher speed. The transmit and receive channels
adapt independently, each detecting and adjusting to line conditions.
Calls to and from Modems and Fax Machines
When used with fax-capable communications software, your Courier
auto-detects and responds to calls from modems and Group III fax
machines using EIA-standard Class 1 or 2.0 fax software.
Data Compression
 
V.42 bis/MNP5
Data compression enables throughput of up to 230.4 kbps on analog
connections. I-modems connecting under V.42 or HST error control use
V.42bis compression. I-modems connecting under MNP error control use
MNP Level 5 compression. Typically, files can be compressed from 2:1 to
4:1.
Error Control
 
V.42/MNP
Data integrity is ensured when the I-modem connects with remote devices
that use the V.42 (LAPM), HST, or MNP error control protocols. Error
control is available on analog calls at 1200 bps and above.
V.Everything
The Courier provides full support of the x2, V.34 standard, V.Fast Class,
V.32 terbo, and many other modulation schemes, spanning the range of
speeds between 300 bps and 56 kbps.