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S-Registers

Floyd Kling 

(7/23/09)

 

S-Register Quick Look-up

No.   Function No.     Function
S0*  Ring Count to Auto Answer S24   Sleep inactivity Timer

S1    Ring Counter

S25   Delay to DTR off

S2*  Escape Characters

S26   RTS to CTS Delay

S3    Carriage Return Character

S27   General Bit Mapped Options

S4    Line Feed Character S28   General Bit Mapped Options
S5    Backspace Character S29   Flash Dial Modifier Time
S6*  Wait Time before Blind Dialing or for Dial Tone S30   Disconnect Inactivity Timer
S7*  Wait Time for Carrier, Silence, or Dial Tone S31   General Bit Mapped Options
S8*  Pause Time for Dial Delay Modifier S36*  LAPM Failure Control
S9*  Carrier Detect Response Time S38   Delay Before Forced hang up
S10* Lost Carrier to Hang Up Delay S39   Flow Control Bit Mapped Options
S11* DTMF Tone Duration/Cadence S40* General Bit Mapped Options
S12* Escape Prompt Delay (EPD) S41* General Bit Mapped Options
S14   Egneral Bit Mapped Options S46* Data Compression Control
S16   Test Mode Bit Mapped Options S48   V.42 Negotiation Control
S17   Point of Sale Options Selection S86   Call Failure Indication
S19   Reserved S91   PSTN Transmit Atten Level
S20   Reserved S92   Fax Transmit Atten Level
S21   V.24/General Bit Mapped Options S95* Extended Result Codes
S22   Speaker/Results Bit Mapped Options S210 V.34 Symbol Rate
S23   General Bit Mapped Options  
* Values may be stored in &W(0) or &W1 locations

 

Modem configurations are stored in S-Registers. Each S-Register is an 8 bit register capable of storing a decimal value between 0 and 255. Some S-Registers may not be changeable or assessable to the user.

 

  • The 'S=' command is used to directly modify the S-Register contents in the form of :

ATSn=x<cr> 

Sn Establishes S-register "n" as the last register accessed.

Sn= v Sets S-register "n" to the value "v"

Sn? Reports the value of S-register "n".

 

The parameter n can be omitted, in which case the last S-Register accessed will be assumed. The S can be omitted for the AT=<cr> and AT?<cr> in which case the last S-Register accessed will be assumed.

 

Inputs and outputs are always in decimal format.  If the parameter n or v is outside the valid range, the modem will return ERROR.  

Note:  In some cases writing to the S register may appear to be accepted but the value will not actually be written, also some S-Parameters are read-only.

In order to avoid confusion, the S-Registers are separated into two types; regular and bit mapped.

 

The regular type is fairly easy to understand while the bit mapped type should be left to experienced personnel. Some S-Registers share functionality with AT commands. i.e changing the an 'AT' parameter will automatically change the shared S-Register, and visa versa. In those cases only the AT Command is documented herein. The corresponding S-register is designated as 'bit mapped' or 'reserved'

 


 

S0 Rings count before Auto Answer

Determines modems auto answer function. A value of 0 disables the auto answer. A value of n greater than 0 will automatically answer after n rings. Zero (0) will disable auto answer.

 

Default: 0 (for most modems)

Range: 0-255 Rings

Saved In &W: Yes

 

S1 Ring count

Counts the number of detected rings . It is cleared to zero if no rings are detected over an 8-second interval. This is a read-only register.

 

Default: 0

Range: 0-255 Rings

Saved In &W: NA

 

 

S2 Escape Character

Contains the decimal value of the ASCII character used for the escape character (well known as +++)

 

Default: 43 (+..plus sign)

Range: 0-255

Saved In &W: Yes

 

S3 Carriage return <cr> character

Contains the decimal value of the ASCII character for the carriage return character

 

Default: 13 <cr>

Range: 0-127

Saved In &W: No

 

 

 

S4 Line Feed Character

Contains the decimal value of the ASCII character used for the line-feed character:

 

Default: 10 (line feed)

Range: 0-127

Saved In &W: No

 

 

 

S5 Back Space Character

Contains the decimal value of the ASCII character used for the back space character

 

Default: 8 (backspace)

Range: 0-255

Saved In &W: No

 

S6 Wait Before Dialing

Contains the value (in seconds) that determines the time the modem must wait before dialing.

 

Default: 2 (seconds)

Range: 2-255 seconds

Saved In &W: yes

 

 

S7 Wait For Carrier

Contains the number of seconds the modem will wait for carrier in both the answer and originate modes. If no carrier is detected by this time setting, the modem will hang-up and return to IDLE mode. This value is country dependent.

 

Default: 50 (seconds)

Range: 1-255

Saved In &W: Yes

 

S8 Pause

Designates the pause time in seconds for each (,)comma encountered in the dial string.

 

Default: 2 (seconds)

Range: 0-255

Saved In &W:

 

S9 DCD (Carrier Detect) Response Time

Designates the carrier detect response time. Measured in tenths of a second. Default: 6 (0.6 seconds)

 

Default:6 (.6 seconds)

Range: 1-255 (0.1sec increments)

Saved In &W: Yes

 

S10 Delay Between Loss of Carrier and Hang-Up

Contains the value that establishes the delay time, in tenths of second, between the loss of carrier (DCD changing to low) and modem hanging-up.

 

Default: 14 (1.4 seconds)

Range: 1-255 (0.1 sec increments)

Saved In &W: Yes

 

S11 DTMF Duration and Spacing

Contains the value representing the duration and inter-digit time, in milliseconds, for DTMF tones generated by the modem during tone dialing. This value is country dependent.

 

Default: 95 (ms)  (That's 95ms tone "on", followed by 95ms tone "off")

Range: 50-255 (0.001ms increments)

Saved In &W: Yes

 

S12 Escape Prompt Delay

Defines the maximum period, in 1/50 of a second, allowed between receipt of the last character of the escape character sequence and returning an "OK". If any characters are detected during this time, the OK will not be returned. Sending of the OK does not affect entry into the command mode.

 

Default: 50 (1 second)

Range: 0-255 (0.02s increments)

Saved In &W: Yes

 

 

S13 Reserved

 

 

S14 Bit Mapped with various AT Commands (En, Qn, Vn T, P)

 

Default: 138 (8Ah)

Range:

Saved In &W:

 

 

S16 Bit Mapped with Test commands (&T)

 

Default: 0

Range:

Saved In &W:

 

S17 Reserved

 

Default: 0

Range:

Saved In &W:

 

 

S18 Reserved

 

Default: 0

Range:

Saved In &W:

 

S19 Reserved

 

Default: 0

Range:

Saved In &W:

 

 

S20 Reserved

 

Default: 0

Range:

Saved In &W:

 

 

S21 Bit Mapped with various AT commands (&Rn, &Dn, &Cn, &Sn, Yn)

 

Default: 52 (34h)

Range:

Saved In &W:

 

 

S22 Bit Mapped with various AT commands (Ln, Mn, Xn)

 

Default: 117 (75h)

Range:

Saved In &W:

 

 

S23 Bit Mapped with various AT commands (&Gn)

 

Default: 0

Range:

Saved In &W:

 

 

S24 Sleep Inactivity Timer.

Contains the length of time, in seconds, that the modem will operate in normal mode with no DTE activity before entering low-power sleep mode. Timer is reset upon any activity on the DTE interface. If S24=0 this timer is disabled. This feature is not available on all models

 

Default: 0 (Seconds)

Range: 0-255

Saved In &W:

 

S25 Delay Between Loss of DTR and Hang-up

Determines the delay time between the loss of DTR and hang-up. The value of this register differs depending on the operation in effect: In Synchronous mode, when configured for &M1, this time is measured in seconds; when configured for &M2 or &M3, this delay is measured in hundredths of a second.

 

Default : 5   (.05 sec when in Async mode) -or- (5 sec when in Synchronous Mode)

Range: 0-255

Saved In &W:

 

 

S26 Delay between RTS and CTS

Determines the period of time the modem waits before turn on Clear To Send (CTS) after detecting Request to Send (RTS). Measured in hundredths of a second.

 

Default: 1 (0.01 seconds)

Range: 0-255 (in 0.01 sec increments)

Saved In &W:

 

 

S27 Bit Mapped with various AT commands (&Mn, &Ln, &Xn, &Bn)

 

Default: 73 (49h)

Range:

Saved In &W:

 

 

S28 Bit Mapped with various AT commands (&Pn

 

Default: 0

Range:

Saved In &W:

 

 

S29 Hook Flash Dial Modifier Time

Sets the length of time in units of 10ms, that the modem will go on hook when it encounters the flash (!) dial modifier in the dial string. The time can be limited as it is a country dependent parameter.

 

Default: 70 (700ms)

Range: 0-255 (in 10ms increments)

Saved In &W:

 

 

S30 Disconnect Inactivity Timer

Set the time, in tenths of seconds, that the modem will stay on line before disconnecting when no data is sent or received. (Dead man on keyboard). In error correction mode, any data sent or received will reset the timer. In other modes, any data sent will reset the timer. Timer is disabled in synchronous modes.

 

Default: 0 (disabled)

Range: 0-255 (in 10 second increments)

Saved In &W:

 

 

S31 Bit Mapped with various AT commands (\Vn, Wn, #CID)

 

Default: 192 (C0h)

Range:

Saved In &W:

 

S36 LAP-M Failure Control

Determines how the modem should react to a LAP-M failure. The fallback options are initiated immediatly upon connection if S48=128.  If an invalid number is entered, the number is accepted into the reguster, but S36 will act as if the default value(7) has been entered

Default: 7

Range:

Saved In &W: Yes

 

BITS 0-2

0:  Modem disconnects

1:  Modem stays on-line and a direct modem connection is established

2:  Reserved

3:  Modem stays on-line and a normal modem connection is established

4:  An MNP connetion is attempted and if it fails, the modem disconnects

5:  An MNP connectin is attempted and if it fails, a direct mode connection is established.

6:  Reserved

7:  An MNP connection is attempted and if it fails, a normal mode connection is established (DEFAULT)

 

 

S38 Delay before forced Hang up.

Specifies the delay between the modems receipt of the H command to disconnect or ON to OFF transition of DTR Applicable to error-correction connections only. This register can be used to ensure that data in the modem buffer is sent before the modem disconnects.

 

Default: 20

Range: 0-255 (in seconds increments)

Saved In &W:

 

 

S39 Bit Mapped with Flow control options (&Kn)

 

Default: 3

Range:

Saved In &W:

 

 

S40 Bit Mapped with MNP and break handling (-Kn, \Kn)

 

Default: 104 (68h)

Range:

Saved In &W: Yes

 

 

S41 Bit mapped with Compression retrain, and fallback. (%C, %E)

 

Default: 195 (C3h)

Range:

Saved In &W: Yes

 

 

S46 Data Compression Control

S46 controls selection of compression.  The following actions are executed for the given values

136:  Execute error correction protocol with no compression.

138:  Execute error correction protocol with compression DEFAULT

 

Default: 138

Range: 136 or 138

Saved In &W: Yes

 

 

S48 V.42 negotiation action

The S48 register controls V.42 negotiation

 

0:  Disable negotiation and proceeds with :AP-M

7:  Enable negotiation. DEFAULT

128:  Disables negotiation and proceeds with the fallbck action specified by S36

Default: 7

Range: 0, 7, or 128  If an invalid number is entered, it is accepted into the S-Parameter, but S48 will act as if 128 has been entered

 

Saved In &W:

 

 

S86 Call failure Reason Code

When the modem fails to connect a corresponding value is written to this register that indicates the reason for failure. This register helps determine the reason for the failed connection of a previous call. (To inspect this register, enter ATS86?<cr>)

 

Default: 21

Range: 0-26 (for Inspection Only)

Saved In &W:

 

0 - Normal hang up, no error occurred

1 - reserved

2 - reserved

3 - Call Waiting caused disconnect

4 - Physical carrier loss

5 - No error correction at other end

6 - No response to feature negotiation.

7 - This modem is async only; the remote modem is sync only

8 - No framing technique in common

9 - No protocol in common

10 - Bad response to feature negotiation

11 - No sync information from the remote modem

12 - Normal hangup initiated by the remote modem

13 - Retransmission limit reached

14 - Protocol violation occurred

15 - Lost DTR

16 - Received GSTN cleardown

17 - Inactivity timeout

18 - Speed not supported

19 - Long space disconnect

20 - Key abort disconnect

21 - Clears previous disconnect reason

22 - No connection established

23 - Disconnect after three retrains

24 - Call waiting tone detected

25 - Extension pickup detected

26 - Remote hangup detected

 

 

S91 PSTN Transmit Attenuation Level

 

Default: 10 (Country Dependent)

Range: 0-15 (in dbm)

Saved In &W:

 

 

S92 Bit mapped with FAX control

 

Default: 10 (Country Dependent)

Range: 0-15 (in dbm)

Saved In &W:

 

 

S95 Extended Result Codes Control (Bit Mapped)

Default: 0

Range:

Saved In &W:

 

 

S210 V.34 Symbol Rates (Bit Mapped)

 

Default: 13 (0Dh)

Range: 0-255

Saved In &W:

 

END

 

 

 

Copyright © 1997-2011 Floyd Kling 
- All Rights Reserved -