S Registers S26 to S95

S26 RTS-to-CTS Delay :

Range : 0-255 Unit : 0.01 seconds Default : 1
This register is only relevant for synchronous operation with &R0 selected. It sets the time delay before the modem turns CTS on after detecting an off-to-on transition on RTS.

S27 General Bit Mapped Options Status :

Range : - Unit : - Default : 9
A Bit mapped option register allows you to check the current settings of various commands. You would not normally alter this register directly because it is easier to use the actual commands themselves. The function of this register is coded in binary and displayed in decimal.
Bits 0,1,3 Synchronous/asynchronous selection (&Mn/&Qn)
3 1 0
0 0 0 = &M0 or &Q0
0 0 1 = &M1 or &Q1
0 1 0 = &M2 or &Q2
0 1 1 = &M3 or &Q3
1 0 0 = &Q4
1 0 1 = &Q5 (Default.)
1 1 0 = &Q6
Bit 2 Leased line control (&Ln)
0 = Dial up line (&L0) (Default.)
Bits 4-5 Internal clock select (&Xn)
0 = Internal clock (&X0) (Default.)
1 = External clock (&X1)
2 = Slave clock (&X2)
Bit 6 CCITT/Bell mode select (Bn)
0 = CCITT mode (B0) (Default.)
1 = Bell mode (B1)
Bit 7 Reserved

S28 General Bit Mapped Options Status :

Range : - Unit : - Default : 8
A Bit mapped option register allows you to check the current settings of various commands. You would not normally alter this register directly because it is easier to use the actual commands themselves. The function of this register is coded in binary and displayed in decimal.
Bits 0-1 Reserved
Bit 2 Reserved (always 0).
Bits 3-4 Pulse dialing (&Pn)
0 = 39%-61% make/break ratio at 10 pulses per second (&P0)
1 = 33%-67% make/break ratio at 10 pulses per second (&P1) (Default.)
2 = 39%-61% make/break ratio at 20 pulses per second (&P2)
3 = 33%-67% make/break ratio at 20 pulses per second (&P3)
Bits 5-7 Reserved

S29 Flash Dial Modifier Time :

Range : 1-15 Unit : 0.01 seconds Default : 7
S29 sets the period of time the modem will go on hook when the "!" modifier is encountered in the dial string before returning off hook. This facility is sometimes useful for transferring calls.

S30 Disconnect Inactivity Timer :

Range : 0-255 Unit : 10 seconds Default : 0
After a successful connection and data transfer the modem will continue to hold the line without transmitting or receiving any further information. If this quiet period exceeds the value specified in S30 the connection will be terminated. This prevents the modem from staying on-line indefinitely when left unattended.

For error corrected connections, each time data is transferred the timer is reset. For non-error corrected connections, only transmitted data resets the timer. The timer is inoperative in synchronous mode. A sensible value in most situations is 10 minutes (i.e. a value of 60). Setting the register to 0 disables the timer.

When in voice mode S30=0 sets the deadman timer to off. No matter how long the period of inactivity lasts, the modem never hangs up the telephone line or switches to auto-baud mode.

When in voice mode S30=n where n has the range 1 to 255. This is the period of time in seconds, which if expired causes the modem to hang up the telephone line if it is off hook and no data has passed during that period. The timer is also active whenever the #BDR setting is non zero. To avoid a state where speed sense is disabled, the inactivity time-out occurs if there is no data passed on the DTE interface within the S30 period, even if the modem is on hook. The DTE software must not select a non zero setting for #BDR until it is ready to establish a telephone call or virtual connection to a speaker or microphone. When there is an inactivity time-out with #CLS=8, the modem always forces #CLS=0 and #BDR=0.

S31 General Bit Mapped Options Status :

Range : - Unit : - Default : 202
A Bit mapped option register allows you to check the current settings of various commands. You would not normally alter this register directly because it is easier to use the actual commands themselves. The function of this register is coded in binary and displayed in decimal.
Bit 0 Single line connect message enable/disable (\Vn)
0 = Messages controlled by S95, Wn and Vn (\V0) (Default)
1 = Single line connect message (\V1)
Bit 1 Auto line speed detection (Nn)
0 = Disabled (N0)
1 = Enabled (N1) (Default.)
Bits 2-3 Error correction progress messages (Wn)
0 = DTE speed only (W0)
1 = Full reporting (W1)
2 = DCE speed only (W2) (Default)
Bits 4-5 Caller ID (#CID)
0 = Caller ID disabled (#CID=0) (Default)
1 = Short (formatted) Caller ID enabled (#CID=1)
2 = Long (unformatted) Caller ID enabled (#CID=2)
Bits 6-7 Reserved (Default = 11b)

S32 XON character :

Range : 0-255 Unit : ASCII Default : 17
The S32 register records the value to be recognised as the XON flow control character. By default this is 17; ASCII DC1.

S33 XOFF character :

Range : 0-255 Unit : ASCII Default : 19
The S33 register records the value to be recognised as the XOFF flow control character. By default this is 19; ASCII DC3.

S36 LAPM Failure Control :

Range : 0-255 Default : 7
This register indicates what should happen upon a LAPM negotiation failure. Its value is automatically updated when the appropriate \N command is issued. It is not recommended that you modify this register directly.

0 = the modem disconnects.
1 = modem stays on-line and a direct mode connection is established.
2 = reserved.
3 = modem stays on-line and a normal mode connection is established.
4 = an MNP connection is attempted and if it fails, the modem disconnects.
5 = an MNP connection 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.

S37 Line modulation select :

Range : 0-23 Default : 0
When the N0 command is issued, this register selects the communication mode the modem uses. This combination of the N command and S37 can be used as an alternative to the preferred technique of speed selection using the F or +MS command, but if the 56k speed is set using the +MS command this register will not be affected. Below is a list of the valid values for the register, the mode they select and the corresponding F command.

0 = Automatic mode (F0)
1-3 = V.21 or Bell 103 mode (F1) 15 = V.34 14400 bps (F13)
5 = V.22 or Bell 212A mode (F4) 16 = V.34 16800 bps (F14)
6 = V.22bis mode (F5) 17 = V.34 19200 bps (F15)
7 = V.23 mode (F3) 18 = V.34 21600 bps (F16)
8 = V.32 or V.32bis 4800 bps (F6) 19 = V.34 24000 bps (F17)
9 = V.32 or V.32bis 9600 bps (F8) 20 = V.34 26400 bps (F18)
10 = V.32bis 12000 bps (F9) 21 = V.34 28800 bps (F19)
11 = V.32bis 14400 bps (F10) 22 = V.34 31200 bps (F20)
12 = V.32bis 7200 bps (F7) 23 = V.34 33600 bps (F21)

S38 Delay Before Forced Hangup (error corrected modes only) :

Range : 0-255 Unit : Seconds Default : 20
This register specifies the delay between the modem's receipt of the H command to disconnect (or on-to-off transition of DTR if the modem is programmed to follow the signal), and the disconnect operation. The register can therefore be used to ensure that data in the modem buffer is sent before the modem disconnects.

If S38 is set to a value between 0 and 254, the modem will wait that number of seconds for the remote modem to acknowledge all data in the modem buffer before disconnecting. If time expires before all the data is sent, the NO CARRIER result code will be issued to indicate that the data has been lost. If all data is transferred prior to time-out, the response to the H0 command will be OK.

If S38 is set to 255, the modem does not time-out and continues to attempt to deliver data in the buffer until the connection is lost or the data is delivered.

S39 Flow Control Bit Mapped Options Status :

Range : - Unit : - Default : 131
A Bit mapped option register allows you to check the current settings of various commands. You would not normally alter this register directly because it is easier to use the actual commands themselves. The function of this register is coded in binary and displayed in decimal.
Bits 0-2 Status of command options
0 = No flow control
3 = RTS/CTS (&K3) (Default.)
4 = XON/XOFF (&K4)
5 = Transparent XON (&K5)
6 = Both methods (&K6)
Bits 3-7 Reserved

S40 General Bit Mapped Options Status :

Range : - Unit : - Default : 232
A Bit mapped option register allows you to check the current settings of various commands. You would not normally alter this register directly because it is easier to use the actual commands themselves. The function of this register is coded in binary and displayed in decimal.
Bits 0-1 MNP Extended Services (-Kn)
0 = Disable extended services (-K0)
1 = Enable extended services (-K1) (Default)
2 = Enable extended services (-K2)
Bit 2 Reserved
Bits 3-5 Break Handling (\Kn)
0 = \K0
1 = \K1
2 = \K2
3 = \K3
4 = \K4
5 = \K5 (Default.)
Bits 6-7 MNP block size (\An)
0 = 64 chars (\A0)
1 = 128 chars (\A1)
2 = 192 chars (\A2)
3 = 256 chars (\A3) (Default.)
Bits 3-7 Reserved

S41 General Bit Mapped Options Status :

Range : - Unit : - Default : 195
A Bit mapped option register allows you to check the current settings of various commands. You would not normally alter this register directly because it is easier to use the actual commands themselves. The function of this register is coded in binary and displayed in decimal.
Bits 0-1 Compression selection (%Cn)
0 = Disabled (%C0)
1 = MNP 5 (%C1)
2 = V.42 bis (%C2)
3 = MNP 5 and V.42 bis (%C3) (Default.)
Bits 2, 6 Auto retrain and fallback/fall forward (%En)
6 2
0 0 = Retrain and fallback/fall forward disabled (%E0)
0 1 = Retrain enabled (%E1)
1 0 = Fallback/fall forward enabled (%E2) (Default.)
Bits 3-5 Break Handling (\Kn)
0 = \K0
1 = \K1
2 = \K2
3 = \K3
4 = \K4
5 = \K5 (Default.)
Bits 3-5 Reserved
Bit 7 Reserved

S46 Data Compression Control :

Range : 0-255 Unit : - Default : 138
Controls selection of compression. The following actions are executed for the given values:

S46=136 Execute error correction protocol with no compression.
S46=138 Execute error correction protocol with compression. (Default.)

S48 V.42 Negotiation Control :

Range : 0-255 Unit : - Default : 7
This register stores settings relating to V.42 connection negotiations. Its value is automatically updated when the appropriate \N command is issued. It is not recommended that you modify this register directly.

S82 LAPM Break Control :

Range : 0-255 Default : 128
Break signals provide a way for the user to get the attention of the remote modem. The break type depends on the specific application. LAPM specifies three methods of break signal handling: in sequence, expedited, and destructive. If an invalid number is entered, it is accepted into the S register, but S82 will act as if the default value has been entered.

S82=3 Expedited: Modem sends a break immediately; data integrity is maintained both ahead of and after the break.
S82=7 Destructive: Modem sends a break immediately; data being processed by each modem at the time of the break is destroyed.
S82=128 In sequence: Modem sends a break in sequence with any transmitted data; data integrity is maintained both ahead of and after the break. (Default.)

S86 Call failure reason code :

Range : 0, 4-20 Default : 0
When the modem issues a NO CARRIER result code, a value is written to this S register. It records the first event that contributes to the NO CARRIER message. The reason codes are:

0 = Normal hangup, no error occurred
4 = Loss of carrier.
5 = V.42 negotiation failed to detect an error-correcting modem at other end.
6 = No response to feature negotiation.
7 = This modem is asynchronous only; the other modem is synchronous only.
8 = No framing technique in common.
9 = The modems could not find a common protocol.
10 = Bad response to feature negotiation.
11 = No sync information from remote modem.
12 = Normal disconnect initiated by the remote modem.
13 = The remote modem did not respond after 10 re-transmissions of the same message.
14 = Error correction protocol violation.
15 = DTR has been lost.
16 = Remote hang-up initiated by GSTN cleardown.
17 = Inactivity time-out.
18 = Speed not supported.
19 = Long space disconnect.
20 = Key abort disconnect.

S95 Result code/message control :

Range : 0-255 Default : 2
Individual bits in register S95 select up to five options relating to enhanced connect messages. Some of the changes effected by this register may more easily be achieved by the use of the W command. Indeed, the W command overrides some of the settings selected with S95.

The options may be individually enabled in any combination. There is a decimal value corresponding to each message option available which must be entered in the register. To select more than one option at a time, add the decimal values corresponding to each option together and enter the sum total into the register.

Bit Decimal Description
0 1 The connect message always reflects the line speed instead of the DTE speed
1 2 The suffix /ARQ is added to the connect message for any error corrected connections
2 4 A CARRIER XXXX message describing the line speed of the connection is displayed before the connect message
3 8 A PROTOCOL: XXXX message describing the type of error correction protocol in use is displayed before the connect message
4 0 Reserved
5 32 A COMPRESSION: XXXX message describing the type of data compression in use is displayed before the connect message
6 0 Reserved
7 0 Reserved

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