US Robotics COURIER User Manual page 17

COURIER HIGH SPEED MODEMS
Data Compression-V.42 bis/MNP5
Data compression enables potential throughput of well over
SOK bps on 14.4K or 16.8K bps connections. Couriers connecting
under V.42 or HST error control use V.42 bis compression.
Couriers connecting under MNP error control use MNP Level 5
compression. Achievable throughput of text and other types of
files is listed in Appendix A.
Flow ControlNariable Interface Rates
Flow control, required under error control, also allows the local
computer interface rate to be set higher than the link rate,
enabling greater efficiency and throughput. If your equipment
and software support high rates, data can be sent from the com-
puter to the modem at 57.6K, 38.4K or 19.2K bps, regardless of
the link rate.
Voice/Data Switch
Users have always been able to phone and make arrangements
with another user before turning control of the call over to the
modems. A new feature, a switch on the modem's front panel,
allows you to change from voice to data and back again, without
issuing a command.
If you don't ordinarily use voice and data in the same call, you
can assign the switch a different function that normally requires
a command, such as resetting the modem or executing a stored
command string. See Appendix E, Voice/Data, for instructions on
voice/ data switching.
Stored Command String
You can store a command string in nonvolatile random access
memory that is executable at a touch of the voice/ data switch.
Asynchronous/Synchronous Capability
Courier high speed modems operate synchronously as well as
asynchronously. A personal computer equipped with a synchro-
nous interface adapter can call computers that use standard
synchronous protocols. See Chapter 7 for more information.
1-2 Features and Compatibility
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