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The S-Registers are summarized in the following table along with their default values. Registers denoted with an '*' may be stored in one of the two user profiles by entering the &Wn command. One of these profiles may be loaded at any time by using the Zn command. Registers or register fields quoted as "reserved" are reserved for current or future use by the firmware, or are permanently overridden by PTT limitations.
All bit-mapped registers are read-only. The appropriate AT command which controls the relevant bits in the S-Register should be used to change the value.
The factory default values are stored in ROM and are loaded into the active configuration at power up or by the ATZn command. In addition, the designated default profile is subsequently loaded, and may change some of the factory default values. The designated default profile can be changed by entering the &Yn command where n is one of the two possible user profiles.
The default values shown in the table may vary by modem firmware configuration. Consult the MCU firmware release notes for exact configuration.
The factory default values may be loaded at any time by entering the &Fn command.
Register Function Range Units Saved Default** S0 Rings to Auto-Answer 0-255 rings * 0 country dependent S1 Ring Counter 0-255 rings 0 S2 Escape Character 0-255 ASCII * 43 S3 Carriage Return Character 0-127 ASCII 13 S4 Line Feed Character 0-127 ASCII 10 S5 Backspace Character 0-255 ASCII 8 S6 Wait Time for Dial Tone 2-255 s * 2 country dependent S7 Wait Time for Carrier 1-255 s * 50 country dependent S8 Pause Time for Dial Delay 0-255 s * 2 country dependent Modifier S9 Carrier Detect Response Time 1-255 0.1 s * 6 S10 Carrier Loss Disconnect Time 1-255 0.1 s * 14 S11 Reserved S12 Escape Prompt Delay 0-255 0.02 s * 50 S13 Reserved - - - S14 General Bit Mapped Options - - * 138 (8Ah) Status S15 Reserved - - - S16 Test Mode Bit Mapped - - 0 Options Status (&T) S17 Reserved - - - S18 Test Timer 0-255 s * 0 S19 AutoSync Options - - 0 S20 AutoSync HDLC Address or 0-255 - * 0 BSC Sync Character S21 V.24/General Bit Mapped - - * 52 (34h) Options Status S22 Speaker/Results Bit Mapped - - * 117 (75h) Options Status S23 General Bit Mapped Options - * 54 (36h) Status S24 Sleep Inactivity Timer 0-255 s * 0 S25 Delay to DTR Off 0-255 s or 5 0.01 s S26 RTS-to-CTS Delay 0-255 0.01 s 1 S27 General Bit Mapped Options - - * 73 (49h) Status S28 Reserved S29 Flash Dial Modifier Time 0-255 10 ms 70 country dependent S30 Disconnect Inactivity Timer 0-255 10 s 0 S31 General Bit-Mapped Options - - * 194 (C2h) Status S32 XON Character 0-255 ASCII 17 (11h) S33 XOFF Character 0-255 ASCII 19 (13h) S34-S35 Reserved - - - S36 LAPM Failure Control - - * 7 S37 Line Connection Speed - - * 0 S38 Delay Before Forced Hangup 0-255 s 20 S39 Flow Control Bit Mapped - - * 3 Options Status S40 General Bit-Mapped Options - - * 104 (68h) Status S41 General Bit-Mapped Options - - * 195 (C3h) Status S42-S45 Reserved - - - S46 Data Compression Control - - * 138 S48 V.42 Negotiation Control - - * 7 S82 LAPM Break Control - - 128(40h) S86 Call Failure Reason Code 0-255 - - S91 PSTN Transmit Attenuation 0-15 dBm 10 country dependent Level S92 Fax Transmit Attenuation 0-15 dBm 10 country dependent Level S95 Result Code Messages Control - - * 0 * Register value may be stored in one of two user profiles with the &W command.
Sets the number of the rings required before the modem automatically answers a call. Setting this register to zero disables auto-answer mode.
Range: 0-255 rings (country dependent PTT restrictions)
Default: 0
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 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 (+)
Sets the command line and result code terminator character. Pertains to asynchronous operation only.
Range: 0-127, ASCII decimal
Default: 13 (Carriage Return)
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)
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)
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.
2. For W-class models, S6 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.
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 (country dependent PTT restrictions)
Default: 2
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. For US models, S7 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.
Range: 1-255 seconds (country dependent PTT restrictions)
Default: 50
Sets the time, in seconds, that the modem must pause when the "," dial modifier is encountered in the dial string.
Range: 0-255 seconds (country dependent PTT restrictions)
Default: 2
Sets the time, in tenths of a second, that the carrier must be present before the modem considers it valid and turns on RLSD. As this time is increased, there is less chance to detect a false carrier due to noise from the telephone line.
Range: 1-255 tenths of a second
Default: 6 (0.6 second)
Sets the length of time, in tenths of a second, that the modem waits before hanging up after a loss of carrier. This allows for a temporary carrier loss without causing the local modem to disconnect. When register S10 is set to 255, the modem functions as if a carrier is always present.
The actual interval the modem waits before disconnecting is the value in register S10 minus the value in register S9. Therefore, the S10 value must be greater than the S9 value or else the modem disconnects before it recognizes the carrier.
Range: 1-255 tenths of a second
Default: 14 (1.4 seconds)
Defines the maximum period, in fiftieths of a second, allowed between receipt of the last character of the three escape character sequence from the DTE and sending of the OK result code to the DTE. If any characters are detected during this time, the OK will not be sent. Note that sending of the OK result code does not affect entry into command mode. (See 3.1.3.)
Range: 0-255 1/50 of a second
Default: 50 (1 second)
Indicates the status of command options.
Default: 138 (8Ah) (10001010b)
Bit 0 This bit is ignored.
Bit 1 Command echo (En)
0 = Disabled (E0)
1 = Enabled (E1) (Default.)
Bit 2 Quiet mode (Qn)
0 = Send result codes (Q0) (Default.)
1 = Do not send result codes (Q1)
Bit 3 Result codes (Vn)
0 = Numeric (V0)
1 = Verbose (V1) (Default.)
Bit 4 Reserved
Bit 5 Tone (T)/Pulse (P)
0 = Tone (T) (Default.)
1 = Pulse (P)
Bit 6 Reserved
Bit 7 Originate/Answer
0 = Answer
1 = Originate (Default.)
Indicates the test in progress status.
Default: 0
Bit 0 Local analog loopback
0 = Disabled (Default.)
1 = Enabled (&T1)
Bit 1 Not used
Bit 2 Local digital loopback
0 = Disabled (Default.)
1 = Enabled (&T3)
Bit 3 Remote digital loopback (RDL) status
0 = Modem not in RDL (Default.)
1 = RDL in progress
Bit 4 RDL requested (AT&T6)
0 = RDL not requested (Default.)
1 = RDL requested (&T6)
Bit 5 RDL with self test
0 = Disabled (Default.)
1 = Enabled (&T7)
Bit 6 Local analog loopback (LAL) with self test
0 = Disabled (Default.)
1 = Enabled (&T8)
Bit 7 Not used
Sets the length of time, in seconds, that the modem conducts a test (commanded by &Tn) before returning to the command mode. If this register value is zero, the test will not automatically terminate; the test must be terminated from the command mode by issuing an &T0 or H command. When S18 is non-zero, the modem returns the OK message upon test termination.
Range: 0-255 seconds
Default: 0
Defines the options for AutoSync operation (see &Q4 command). S19 must be set to the desired value before &Q4 is issued.
Default: 0
Bit 0 Reserved
Bit 1 BSC/HDLC format select
0 = BSC selected (Default.)
1 = HDLC selected
Bit 2 Address detection enable/disable
0 = Disabled (Default.)
1 = Enabled
Bit 3 NRZI/NZI coding select
0 = NRZI (Default.)
1 = NZI
Bit 4 Idle indicator select
0 = Mark idle (Default.)
1 = Flag or sync idle
Bits 5 - 7 Reserved
Defines the HDLC address (S19 bit 1 = 1) or BSC Sync Character (S19 bit 1 = 0) for AutoSync operation (see &Q4 command). S20 must be set to the desired value before &Q4 is issued.
Range: 0-255
Default: 0
Indicates the status of command options.
Default: 52 (34h) (00110100b)
Bit 0 Set by &Jn command but ignored otherwise.
0 = &J0 (Default.)
1 = &J1
Bit 1 Reserved
Bit 2 CTS behavior (&Rn)
0 = CTS tracks RTS (&R0)
1 = CTS always on (&R1) (Default.)
Bits 3-4 DTR behavior (&Dn)
0 = &D0 selected
1 = &D1 selected
2 = &D2 selected (Default.)
3 = &D3 selected
Bit 5 RLSD (DCD) behavior (&Cn)
0 = &C0 selected
1 = &C1 selected (Default.)
Bit 6 DSR behavior (&Sn)
0 = &S0 selected (Default.)
1 = &S1 selected
Bit 7 Long space disconnect (Yn)
0 = Y0 (Default.)
1 = Y1
S22 - Speaker/Results Bit Mapped Options Status
Indicates the status of command options.
Default: 117 (75h) (01110101b)
Bits 0-1 Computer speaker volume (Ln)
0 = Off (L0)
1 = Low (L1) (Default.)
2 = Medium (L2)
3 = High (L3)
Bits 2-3 Computer speaker control (Mn)
0 = Disabled (M0)
1 = Off on carrier (M1) (Default.)
2 = Always on (M2)
3 = On during handshake (M3)
Bits 4-6 Limit result codes (Xn)
0 = X0
4 = X1
5 = X2
6 = X3
7 = X4 (Default.)
Bit 7 Reserved
Indicates the status of command options.
Default: 62 (3Dh) (00111110b)
Bit 0 Grant RDL
0 = RDL not allowed (&T5) (Default.)
1 = RDL allowed (&T4)
Bits 1-3 DTE Rate
0 = 0 - 300 bps
1 = 600 bps
2 = 1200 bps
3 = 2400 bps
4 = 4800 bps
5 = 9600 bps
6 = 19200 bps
7 = 38400 bps or higher (Default.)
Bits 4-5 Assumed DTE parity
0 = even
1 = not used
2 = odd
3 = none (Default.)
Bits 6-7 Guard tone (&Gn)
0 = None (&G0) (Default.)
1 = None (&G1)
2 = 1800 Hz (&G2)
Sets the length of time, in seconds, that the modem will operate in normal mode with no detected telephone line or DTE line activity before entering low-power sleep mode. The timer is reset upon any DTE line or telephone line activity. If the S24 value is zero, neither DTE line nor telephone inactivity will cause the modem to enter the sleep mode.
Range: 0-255 seconds
Default: 0
Sets the length of time that the modem will ignore DTR for taking the action specified by &Dn. Its units are seconds for synchronous modes and one hundredths of a second for other modes.
Range: 0-255 (1 second for synchronous modes 1; 0.01 second otherwise)
Default: 5
Sets the time delay, in hundredths of a second, before the modem turns CTS ON after detecting an OFF-to-ON transition on RTS when &R0 is commanded. Pertains to synchronous operation only.
Range: 0-255 hundredths of a second
Default: 1
Indicates the status of command options.
Default: 73 (49h) (01001001b)
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)
1 = Bell mode (B1) (Default.)
Bit 7 - Reserved
Sets the length of time, in units of 10 ms, 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.
Range: 0-255 10 ms intervals (country dependent PTT restrictions)
Default: 70 (700 ms)
Sets the length of time, in tens of seconds, that the modem will stay online before disconnecting when no data is sent or received. In error-correction mode, any data transmitted or received will reset the timer. In other modes, any data transmitted will reset the timer. The timer is inoperative in synchronous mode.
Range: 0-255 tens of seconds (0-2550 seconds)
Default: 0 (disabled)
Default: 194 (C2h) (11000010b)
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) (Default)
1 = Full reporting (W1)
2 = DCE speed only (W2)
Bits 4-5 Reserved
Bits 6-7 Reserved (Default = 11b)
Sets the value of the XON character.
Range: 0-255, ASCII decimal
Default: 17 (11h)
Sets the value of the XOFF character.
Range: 0-255, ASCII decimal
Default: 19 (13h)
Default: 7 (00000111b)
Bits 0-2 This value indicates what should happen upon a LAPM failure. These fallback options are initiated immediately upon connection if S48=128. If an invalid number is entered, the number is accepted into the register, but S36 will act as if the default value has been entered.
0 = 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. (Default.)
Bits 3-7 Reserved
This register specifies the desired line connection speed.
Notes:
1. When the Nn command is issued or the S37 register value is modified, the +MS command subparameters are updated to reflect the speed and modulation specified by the S37 value (see +MS command). For example:
If N0 command is active, S37=10 updates the +MS command subparameters to reflect +MS=10,1,300,12000
If N1 command is active, S37=10 updates the +MS command subparameters to reflect +MS=10,0,12000,12000
2. S37 is not updated by the +MS command.
3. Use of the +MS command is recommended instead of the Nn and S37=x commands. Nn and S37=x commands are supported for compatibility with existing communication software.
Default: 0
Bits 0-4 Desired line connection speed. This is interlinked with the Fn command (RC144). If an invalid number is entered, the number is accepted into the register, but S37 will act as if the default value has been entered.
0 = Attempt automode connection. If N0 is active, connection is attempted at the most recently sensed DTE speed (+MS command settings are updated to the appropriate values). If N1 is active, connection is attempted at the highest possible speed (+MS settings are updated to 11,1,300,2880 to reflect V.34, automode, 300 bps minimum speed, and 28800 bps maximum speed). (Default.)
1-3 = Attempt to connect at 300 bps. F1 command (RC144).
4 = Reserved.
5 = Attempt to connect at V.22 1200 bps. F4 command (RC144).
6 = Attempt to connect at V.22 bis 2400 bps. F5 command (RC144).
7 = Attempt to connect at V.23.
8 = Attempt to connect at V.32 bis/V.32 4800 bps. F6 command (RC144).
9 = Attempt to connect at V.32 bis/V.32 9600 bps. F8 command (RC144).
10 = Attempt to connect at V.32 bis 12000 bps. F9 command (RC144).
11 = Attempt to connect at V.32 bis 14400 bps. F10 command (RC144).
12 = Attempt to connect at V.32 bis 7200 bps. F7 command (RC144).
Bits 5-7 Reserved
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. Applicable to error-correction connection only. This register can be used to ensure that data in the modem buffer is sent before the modem disconnects.
1. 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 data is sent, the NO CARRIER result code will be issued to indicate that data has been lost. If all data is transmitted prior to time-out, the response to the H0 command will be OK.
2. 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.
Range: 0-255 seconds
Default: 20
Default: 3 (00000011b)
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
Indicates the status of command options.
Default: 104 (68h) (01101000b)
Bits 0-1 MNP Extended Services (-Kn)
0 = Disable extended services (-K0) (Default)
1 = Enable extended services (-K1)
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) (Default.)
2 = 192 chars (\A2)
3 = 256 chars (\A3)
Indicates the status of command options.
Default: 195 (C3h) (11000011b)
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)
Bit 6 Bit 2
0 0 = Retrain and fallback/fall forward disabled (%E0)
0 1 = Retrain enabled (%E1)
1 0 = Fallback/fall forward enabled (%E2) (Default.)
Bit 3 Reserved
Bits 4-5 Reserved
Bit 7 Reserved
Controls selection of compression. The following actions are executed for the given values:
Range: 136 or 138
Default: 138
S46=136 Execute error correction protocol with no compression.
S46=138 Execute error correction protocol with compression. (Default.)
The V.42 negotiation process determines the capabilities of the remote modem. However, when the capabilities of the remote modem are known and negotiation is unnecessary, this process can be bypassed if so desired.
Range: 0, 7, or 128 If an invalid number is entered, it is accepted into the S-Register, but S48 will act as if 128 has been entered.
Default: 7
S48=0 Disable negotiation; bypass the detection and negotiation phases; and proceed with LAPM.
S48=7 Enable negotiation. (Default.)
S48=128 Disable negotiation; bypass the detection and negotiation phases; and proceed at once with the fallback action specified in S36. Can be used to force MNP.
S82 is for compatibility purposes only, changing this register will not have any affect.
When the modem issues a NO CARRIER result code, a value is written to this S-Register to help determine the reason for the failed connection. S86 records the first event that contributes to a NO CARRIER message. The cause codes are:
Range: 0, 4, 5, 9, 12, 13, or 14
Default:
S86=0 Normal disconnect, no error occurred.
S86=4 Loss of carrier.
S86=5 V.42 negotiation failed to detect an error-correction modem at the other end.
S86=9 The modems could not find a common protocol.
S86=12 Normal disconnect initiated by the remote modem.
S86=13 Remote modem does not respond after 10 re-transmissions of the same message.
S86=14 Protocol violation.
Sets the transmit attenuation level from 0 to 15 dBm for the PSTN mode, resulting in a transmit level from 0 to -15 dBm, In some countries, the transmit level may not be changed.
Range: 0 to 15 dBm (Corresponding to 0 to -15 dBm transmit level.) (country dependent PTT restrictions)
Default: 10 (-10 dBm transmit level.)
Sets the transmit attenuation level from 0 to 15 dBm for the fax mode, resulting in a transmit level from 0 to -15 dBm. In some countries, the transmit level may not be changed.
Range: 0 to 15 dBm (Corresponding to 0 to -15 dBm transmit level.) (country dependent PTT restrictions)
Default: 10 (-10 dBm transmit level.)
The bits in this register can be set to override some of the Wn command options. A bit set to a 1 in this register will enable the corresponding result code regardless of the Wn setting. Also, refer to Table 3-1.
Default: 0
Bit 0 CONNECT result code indicates DCE speed instead of DTE speed.
Bit 1 Append/ARQ to CONNECT XXXX result code in error-correction mode (XXXX = rate; see Table 3-1).
Bit 2 Enable CARRIER XXXX result code (XXXX = rate; see Table 3-1. If a V.FC connection is established, /VFC is appended to the CARRIER XXXX message, e.g., CARRIER 28800/VFC; note that there is no short form for this message (RC288).
Bit 3 Enable PROTOCOL XXXX result code (XXXX = protocol identifier; see Table 3-1).
Bit 4 Reserved.
Bit 5 Enable COMPRESSION result code (XXXX = compression type; see Table 3-1).
Bit 6 Reserved.
Bit 7 Reserved.
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