User`s manual

U.S. Robotics I-modem Command Reference
Handshaking, Error Control, Data Compression, and Throughput • Page 11-14
&M6 Start V.25bis synchronous mode, using a character-oriented link protocol
similar to BISYNC. (External I-modems only.)
&M7 Start V.25bis synchronous mode, using the HDLC link protocol. (External
I-modems only.)
Data Compression
I-modems employ different data compression techniques during analog and TurboPPP
(digital) connections.
TurboPPP
When a call uses TurboPPP, the I-modem supports three kinds of compression: Ascend,
Microsoft, and Stac. Compression is available only when the remote device requests one
of the three supported compression types.
Compression for TurboPPP calls is controlled by the &K command. By default, compres-
sion is enabled. Set &K0 to disable compression.