Toshiba Satellite 2450 User Manual page 221

* EC stands for the Error Control method, which appears only when the extended
result codes configuration option is enabled. EC is replaced by one of the
following symbols, depending on the error control method used.
V42bis
V42
NoEC
AT Command
-V90=* V.90 Dial Line Rate
-V90 sets the maximum V.90 downstream that the modem attempts to
connect.
-V90=0 V.90 disabled
-V90=1 V.90 enabled: automatic speed selection - maximum modem speed
(default)
V.42 error control and V.42bis data compression
V.42 error control only
No error control protocol
Appendix E
E-3