Chapter 4 - V.22bis Commands
Multi-Tech Systems, Inc. MT2456SMI-22 SocketModem Developer’s Guide
37
S-PARAMETER DEFINITIONS
S0 - Number of Rings to Auto-Answer
S0 sets the number of the rings required before the modem automatically answers a call.
Setting this parameter to zero disables auto-answer mode.
Range: 0-255 rings
Default: 0
S1 - Ring Counter
S1 is incremented each time the modem detects a ring signal on the telephone line. S1 is cleared if no rings occur
over an eight second interval.
Range: 0-255 rings
Default: 0
S2 - Escape Character
S2 holds the decimal value of the ASCII character used as the escape character. The default value corresponds to an
ASCII '+'. A value over 127 disables the escape process, i.e., no escape character will be recognized.
Range: 0-255, ASCII decimal
Default: 43 (+)
S3 - Carriage Return Character
S3 sets the command line and result code terminator character. Pertains to asynchronous operation only.
Range: 0-127, ASCII decimal
Default: 13 (Carriage Return)
S4 - Line Feed Character
S4 sets the character recognized as a line feed. Pertains to asynchronous operation only. The Line Feed control
character is output after the Carriage Return control character if verbose result codes are used.
Range: 0-127, ASCII decimal
Default: 10 (Line Feed)
S5 - Backspace Character
S5 sets the character recognized as a backspace. Pertains to asynchronous operation only. The modem will not
recognize the Backspace character if it is set to a value that is greater than 32 ASCII. 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.
Range: 0-32, ASCII decimal
Default: 8 (Backspace)
S6 - Wait Time before Blind Dialing or for Dial Tone
S6 operation is country dependent.
1. Sets the length of time, in seconds, that the modem will wait before starting to dial after going off-hook when
blind dialing. This operation, however, may be affected by some ATX options according to country restrictions.
The “Wait for Dial Tone” call progress feature (W dial modifier in the dial string) will override the value in register
S6. (U.S.)
2. Sets the length of time, in seconds, that the modem will wait for dial tone when encountering a “W” dial modifier
before returning NO DIAL TONE result code. (Other countries.)
The modem always pauses for a minimum of 2 seconds, even if the value of S6 is less than 2 seconds.
Range: 2-255 seconds
Default: 2
S7 - Wait Time for Carrier, Silence, or Dial Tone
S7 operation is country dependent.
1. Sets the length of time, in seconds, that the modem will wait for carrier before hanging up. The timer is started
when the modem finishes dialing (originate), or 2 seconds after going off-hook (answer). In originate mode, the
timer is reset upon detection of answer tone if allowed by country restrictions.
2. Sets the length of time, in seconds, that modem will wait for silence when encountering the @ dial modifier
before continuing with the next dial string parameter.
3. Sets the length of time, in seconds, that the modem will wait for dial tone when encountering a “W” dial modifier
before continuing with the next dial string parameter. (U.S.)
Range: 1-255 seconds
Default: 50
