User`s manual

U.S. Robotics I-modem Command Reference
Glossary • Page G-11
Some protocols, such as USR HST and MNP, employ advanced techniques such as longer
transmission frames and data compression to increase cps.
circuit-switched data (CSD)
A type of switching in which one call makes up a circuit (the circuit is not shared with
other calls), and data is passed across the circuit.
circuit-switched voice (CSV)
A type of switching in which one call makes up a circuit (the circuit is not shared with
other calls), and speech or 3.1 KHz audio is passed across the circuit.
Class 1/EIA-578
An American standard used between facsimile application programs and facsimile
modems for sending and receiving Class 1 faxes.
Class 2.0/EIA-592
An American standard used between facsimile application programs and facsimile
modems for sending and receiving Class 2.0 faxes.