User`s guide

Protocols
6-2 Modem 3600
Auto-Reliable Mode
In auto-reliable mode the modem negotiates to the highest protocol
(LAPM or MNP) common to both modems. However, if a reliable
connection cannot be established, auto-reliable allows the protocol to
fallback to normal mode.
Constant Speed Interface
The modem serial port adapts to the data rate of the DTE and does not
change speed if the DCE-to-DCE data link connects at another speed.
Therefore, the DTE-to-DCE interface speed is constant.
Data Compression
Using MNP Class 5 data compression, the modem can achieve data
throughput approaching 33600 bps. With LAPM data compression, the
modem can achieve data throughput approaching 115200 bps. This
increase in speed is achieved by automatically analyzing the data stream
and reducing the number of bits required to represent the characters.
100% error-free transmission is assured by the application of the MNP
or LAPM error control protocol on the compressed data.
Compression takes place only if the modem detects that the remote
modem supports compression. If not, a reliable connection is made
without compression.
Although data compression is compatible with any type of data, it is
most efficient for ASCII text files. For maximum throughput when
using data compression, the terminal should be set to a higher speed
than the connect speed with the constant speed interface on and flow
control enabled. When transmitting or receiving data files in one
direction, the throughput can be increased for V.42 bis by having extra
buffer and more processor time with the %C2 and %C3 data compression
commands.
Normal Mode
No error control, with or without constant speed DTE interface. Data is
buffered.