Toshiba Portege 2010 User Manual page 177

Appendix D
S-registers
S-registers contain the settings that determine how a number of functions of the
internal modem operate. The contents of the registers are changed automatically
when you modify corresponding settings in your communication software. If
you choose, however, you can display and edit the contents of the registers
manually when the modem is in command mode.
For details on S-registers, refer to the online manual.
D-1