User`s manual

U.S. Robotics I-modem Command Reference
Appendix A: Alphabetic Command Summary • Page A-4
Notes With the exception of the Dial options, I-modems ignore any commands
issued after D in the same command string.
Optional parameters:
P Dial using pulses. Accepted but ignored.
T Dial using tones. Accepted but ignored.
, (Comma) Pause for 2 seconds (or the time in S-re
gister 8).
; (Semicolon) Remain in Command mode
after dialing.
" Dial the letters that follow.
W Wait for a second dial tone before continuing dialing (with X3 or higher).
@ Wait for an answer (with X3, X4, or X7).
/ Pause for 125 milliseconds.