User`s manual

U.S. Robotics I-modem Command Reference
Handshaking, Error Control, Data Compression, and Throughput • Page 11-18
Getting Maximum Throughput
The following guidelines should help you to make the most of the I-modem's advanced
performance features. In many instances, experimentation and experience will indicate
what works best for your applications.
Maximum throughput results when:
¥ The communications software allows Þxing the serial port rate higher than the connec-
tion rate by setting the soft-ware to 230400, 115200, 57600, or 38400 bps and setting the
I-modem to &B1.
If the software automatically switches serial port rates to follow the connection rate, the
I-modem's serial port rate must be also set to follow the connection rate for each call
(&B0) and throughput will be limited.
Installations with specialized software may want to enable a Þxed serial port rate for
ARQ calls and a variable serial port rate for non-ARQ calls. (See the &B2 command in
Chapter 7, Controlling Data Rates
.)
¥ The call is under data compression.
¥ The data is made up of text Þles rather than binary Þles such as .EXE or .COM Þles.