Serial Programming/Modems and AT Commands/S-Registers


S0: Ring to Answer AfterEdit

Defines the number of ring bursts before the modem automatically answers an incoming call. When set to zero, auto-answer is disabled.

S1: Ring CountEdit

(Read only) Counts the number of ring bursts received. Reset to zero after 8 seconds of no ring.

S2: Escape Sequence CharacterEdit

Specifies the ASCII value of the character used in the escape code. (The escape code is the escape character entered three times in succession.) When the modem is in connect state and it receives the escape code, the modem enters command state. Setting register S2 to 128 or above disables the escape code character.

S3: Carriage Return CharacterEdit

Specifies the ASCII value of the carriage return (CR) character. The carriage return terminates command lines and result codes.

S4: Line Feed CharacterEdit

Specifies the ASCII value for the line feed (LF) character. The line feed character follows a carriage return at the end of long-form result codes. Short-form result codes are sent without line feeds.

S5: Backspace CharacterEdit

Specifies the ASCII value for the backspace (BS) character that you can use to edit the command line.

S6: Wait Before Blind DialingEdit

Specifies the time the modem waits after going off-hook before it dials. This is a minimum of 2 seconds, even if register S6 is set to a value less than 2. Register S6 is used only when the X0, X1, or X3 command (Extended Result Codes) is set.

S7: Wait for Carrier after DialingEdit

Specifies the time that the modem waits for one of the following before hanging up:

•Carrier from the remote modem when this modem is in originate or answer mode

•Ringback, only when this modem is in originate mode, and only if X3 or X4 (Extended Result Codes) is set

Register S7 is linked to register S37 so that the two registers share a single value. Changing the value of S7 changes the value of S37, and changing S37 changes S7.

S8: Duration of Delay for Comma Dial ModifierEdit

This register contains the pause time of the (,) dial modifier used in the dial string. Consecutive commas will invalidate the modem's approval if the total pause period exceeds 12 seconds.

S9: Carrier Detect Response TimeEdit

This register contains the time period that a received carrier signal must be present for the modem to recognise it and turn on the DCD signal.

S10: Delay Between Lost Carrier and Hang UpEdit

Specifies the time the modem waits before hanging up after loss of carrier. This waiting period allows the modem to recover from a temporary loss of carrier without breaking the connection. Modems at both ends of the connection should have the same values set. If the S10 values of the two modems are unequal, disconnection occurs when the lower value is reached. When register S10 is set to 255, the modem functions as if carrier were always present; it never hangs up due to loss of carrier. After disconnecting in originate mode, the modem waits a minimum of 5 seconds before going off-hook.

S11: DTMF Multi-Frequency Tone DurationEdit

This register contains the time period of the duration and inter-digital pause of the DTMF dialling tones.

S12: Escape Sequence Guard TimeEdit

S18: Modem Test TimerEdit

S25: DTR DetectionEdit

S26: RTS to CTS IntervalEdit

S30: Inactivity Time-outEdit

S33: AFT OptionsEdit

S36: Negotiation Failure TreatmentEdit

S37: Desired DCE Line SpeedEdit

S38: Delay Before Forced Hang upEdit

S44: Asynchronous Framing Technique SelectionEdit

S46: Error-Control Protocol SelectionEdit

S48: Enabling/Disabling Feature NegotiationEdit

S49: ASB buffer size lower limitEdit

S50: ASB buffer size upper limitEdit

S53: Global PAD ConfigurationEdit

S63: Leased line carrier levelEdit

S69: Link Layer Window SizeEdit

S70: Maximum Number of RetransmissionsEdit

S71: Link Layer Time-outEdit

S72: Loss of Flag Idle Time-outEdit

S73: No Activity Time-outEdit

S74, S75: Minimum Incoming Logical Channel Number (LCN)Edit

S76, S77: Maximum Incoming Logical Channel Number (LCN)Edit

S78, S79: Outgoing Logical Channel Number (LCN)Edit

S80: Packet Layer N20 ParameterEdit

S81: Packet Layer T20 ParameterEdit

S82: Break Signaling TechniqueEdit

S84: Adaptive start up negotiation (ASU)Edit

S85: ASU Negotiation ReportEdit

S86: Connection Failure CauseEdit

S92: MI/MIC OptionsEdit

S93: V.25bis DTE interface speedEdit

S94: Command Mode SelectorEdit

S95: Negotiation Message OptionsEdit

S97: V.32 Automode V.22/V.22bis Probe TimingEdit