Toshiba V.90 - Manual (Page 61)

S-Registers
S-Register values
42
recognize the backspace character if it is set to an ASCII value
greater than 32. This character can be used to edit a command line.
When the echo command is enabled, the modem echoes back to
the local DTE the backspace character, an ASCII space character,
and a second backspace character. This means a total of three
characters are transmitted each time the modem processes the
backspace character.
S6 Wait before dialing
This register sets the length of time, in seconds, that the modem
must wait (pause) after going off-hook before dialing the first digit
of the telephone number. The modem always pauses for a
minimum of two seconds, even if the value of S6 is less than two
seconds. The wait for dial tone call progress feature (W dial
modifier in the dial string) will override the value in register S6.
S7 Connection completion time-out
This register sets the time, in seconds, that the modem must wait
before hanging up because the carrier is not detected. The timer is
started when the modem finishes dialing (originate), or goes off-
hook (answer). In originate mode, the timer is reset upon detection
of an answer tone if allowed by county restriction. The timer also
specifies the wait for silence time for the @ dial modifier in
seconds. S7 is not associated with the W dial modifier.
Range: 0-127, ASCII decimal
Default: 8 (backspace)
Units: ASCII
Range: 2-65
Default: 2
Units: seconds