AT Command Set and Register Summary for MICA Six-Port Modules

This document describes modem AT commands and S registers for Cisco MICA six-port modules.

For information about managing modems in the Cisco AS5300 using Cisco IOS commands, refer to the "Managing Modems" appendix in the Cisco AS5300 Software Configuration Guide publication.

Note The defaults and limits on parameters described in this document are valid for the United States. They may not be appropriate for use in other jurisdictions.

If you have questions or need help, refer to the section "Cisco Connection Online," page 33, for further information.

This document contains the following sections:

Entering AT Commands

Keep in mind the following guidelines when you send AT commands to a modem:

Entering AT command mode involves a reverse Telnet procedure. Table 1 shows how to enter AT command mode from EXEC mode using reverse Telnet.

Note MICA does not support the modem at-mode commands available in Cisco IOS line configuration mode.

**Table 1: Steps for Entering AT Command Mode**
Step	Command	Purpose
1	`>` `telnet` `ip-address` `line#` Trying 172.0.0.1, 2001 ... Open	Open a reverse Telnet connection to the modem. In the command shown here, `ip-address` is the IP address of the access server and `line#` is the two-digit line number of the modem, prefixed by 20. (For example, enter telnet 172.0.0.1 2001 if the IP address is 172.0.0.1 and the modem line number is 1.) If you do not know which line number to use, enter the show line command and check the resulting display for tty numbers that have `inout` in the Modem column. The Telnet connection is open when the word `Open` appears.
2	`at` `OK`	There is no command prompt in AT command mode. To confirm that you are able to enter AT commands, type at and press Return. If you are in AT command mode, the modem returns `OK`.
3	`Ctrl-Shift-6 X` # `disconnect`	When you are finished entering AT commands, you will want to exit AT command mode and return to privileged EXEC mode. To do so, type Ctrl-Sh-6 X (that is, hold down the Control and Shift keys and press 6, then release everything and press X). Enter disconnect to end the Telnet connection.

All commands except A/ (Repeat Last Command) and +++ (Escape code) are preceded by the AT prefix and are executed when you press Return or Enter.
Commands are limited to 128 characters, not including the AT prefix and Return characters. Dial strings, however, are limited to 49 characters.
Do not enter spaces within AT commands. For example, enter ATS0?, not AT S0?. Dial strings are the exception to this rule. You can enter spaces within a dial string when you use the Dial command, D.
Use the Backspace key (or another key specified in register S5) to erase characters on the command line, except for the leading characters AT. To clear the characters AT, press Return for a fresh command line. For information on changing the command-line erase key, see "S5 (Backspace Character)," page 17.
Type Ctrl-C (^C) to abort a partially entered command. The modem echoes ^C.
Enter commands as either uppercase or lowercase, not mixed case.
A missing numeric argument is assumed to be zero. For example, the Quiet command Q is equivalent to Q0.
The modem operates in the following modes:
- Command state: The modem is idle and waiting for commands.
- Set-up state: Establishing a connection.
- Online state: Connected to another modem.
- Escape state: Allows you to enter commands while the modem is on line. To go to escape state, enter +++ (the Escape code) without pausing and do not press Return. Wait for the OK prompt before entering commands. To return to online state, enter ATO and press Return. You will see a fresh connect message. The escape code can be enabled and disabled; for instructions, see "S47 (Hayes +++ Escape Detection)," page 33.

Alphabetic Command Set

This section describes modem commands that begin with an alphabetic character (A to Z).

A/ (Repeat Last Command)

Re-executes the last command one time. If there has been no previous command, the modem returns OK. A/ is not preceded by the AT prefix and is not followed by a Return.

Note Because of the data forwarding method used in some Telnet connections, it may be necessary to press Return after A/ in some cases.

Forces the modem off-hook in answer mode, regardless of the value of register S11. The modem must be in the idle state when you use the Answer command. If the modem is not in the escape state, it responds to this command with a result code of ERROR.

AT (Attention)

Informs the modem that commands are being sent to it. The modem returns OK. AT must precede all other commands except A/ and +++.

D {dial string} (Dial)

Dials a telephone number, establishing a connection. The Dial command must be the last command on the command line. The dial string can contain up to 49 characters; valid characters are the digits 0 to 9, and for tone dialing, the letters A, B, C, and D and # and *. The modem ignores invalid characters; dial strings longer than 49 characters return the result code ERROR. For example, to dial the telephone number 1 (617) 555-1234, enter the following command:

D 1 (617) 555-1234

The spaces, parentheses, and hyphen in the example's dial string are ignored: they are not dialed and they do not count against the 49-character limit.

To cancel the Dial command, press any key or set data terminal ready (DTR) to off unless &D0 (DTR ignored) is set.

The modem must be in the command state when you use the Dial command. If the modem is in the escape state, it responds to this command with a result code of ERROR.

For compatibility, the modem accepts the following dial modifiers, but does not act on them: P, T, W, , (comma), @, !, and ;

En (Command Echo)

Configures the modem to echo commands to the workstation. Table 2 lists command echo options.

Default

Table 2: Command Echo Options

Command	Meaning
E0	Disables echoing commands to the workstation
E1	Enables echoing commands to the workstation

H (Hang Up)

Disconnects this modem from the remote system and hangs up the telephone line.

In (Inquiry)

Displays modem information and results of checksum tests on firmware. Table 3 lists inquiry command options.

Table 3: Inquiry Command Options

Command	Meaning
I0	Displays the modem product ID code
I1	Runs a checksum on firmware and displays the result
I2	Runs a checksum on firmware and displays the checksum status: 0 (OK in verbose mode) if the checksum is correct 1 (ERROR in verbose mode) if the checksum is not correct
I3	Displays the country code, modulation standards, and revision levels, as shown in this example: `ATI3` `Cisco MICA Hex Modem Module Product Information` `Country Code 001` `V.34+, V.32terbo, V.22bis, V.42, MNP2-4, V.42bis, MNP5` `HEX modem index 00` `CP code revision 2.0.1.6` `CP revision date Sep 20 1997` `SP code revision 2.0.0.7` `SP revision date 06/10/1997 (MM/DD/YYYY)`

Ln (Monitor Speaker Loudness)

This command is provided for compatibility; it has no effect. (The modem responds OK but takes no action.) However, the value of n must be in the range 0 to 3; if another value is used, the modem returns an ERROR result code.

Mn (Monitor Speaker Mode)

This command is provided for compatibility; it has no effect. (The modem responds OK but takes no action.) However, the value of n must be in the range 0 to 2; if another value is used, the modem returns an ERROR result code.

O (Online from Escape Mode)

Sets the modem to the online state (connected, or steady state) from escape mode. The modem displays a connect message.

P (Pulse Dial)

This command is provided for compatibility; it has no effect. (The modem responds OK but takes no action.)

Qn (Quiet)

Configures the modem to send (or not send) result and status codes, such as OK, ERROR, and BUSY, to your workstation. Table 4 lists quiet mode command options.

Note The Q command does not affect output from AT commands such as I, Sn?, \S, and %R.

Default

Table 4: Quiet Mode Command Options

Command	Meaning
Q0	Enables output of result codes
Q1	Disables output of result codes
Q2	Enables output of result codes in originate mode only

Sn (Point to a New Configuration Register)

Sets the modem register pointer to S register n (where n is a decimal number). Register n becomes the current register and is addressed by subsequent register commands. For descriptions of the S registers and a summary of other commands you can use to manipulate S registers, see "Modem S Register Summary," page 14. See also "%R (Verbose Display of the Modem Configuration)," page 9.

Range

0 to 49. (The range equals the numbers of the S registers, which can change from one MICA firmware release to the next as new S registers are added.)

Default

Sn? (Read Configuration Register)

Displays the contents of S register n (where n is a decimal number). For descriptions of the S registers, see "Modem S Register Summary," page 14. See also "%R (Verbose Display of the Modem Configuration)," page 9.

Range

0 to 49

Default

Sn=>y (Set Configuration Register to a Hexadecimal Value)

Sn=y (Set Configuration Register to a Decimal Value)

Sets the contents of S register n (where n is a decimal number) to the value y. For descriptions of the S registers, see "Modem S Register Summary," page 14.

Range

n: 0 to 49
y: depends on n, the register selected

T (Tone Dial)

This command is provided for compatibility; it has no effect. (The modem responds OK but takes no action.)

Vn (Result Code Format)

Selects the format (short or long) of the result codes sent to your workstation. All the result codes are listed and described in Table 5. Table 6 lists result code format command options.

Note The V command does not affect output from AT commands such as I, Sn?, \S, and %R.

Table 5: Result Codes Explained

Numeric Result Code	Long Result Code	Description
0	OK	Command accepted, ready for next command
1	CONNECT	A connection has been established
2	RING	Ring signal indicated
3	NO CARRIER	Indicates one of the following: Carrier signal was not detected Carrier signal was lost for the period specified in register S10 The other modem indicated disconnection (with error correction only) An unrecoverable error occurred (with error correction only)
Center4	ERROR	Indicates one of the following: Invalid command or checksum Command line exceeds 128 characters
Center5	--	Not used
6	NO DIALTONE	Dial tone not detected, or in channelized T1 there was no trunk to seize. (Dial tone detection is enabled by X2 and X4 commands.)
7	BUSY	Busy (line engaged) signal or number unobtainable signal detected. (Busy signal detection is enabled by X3 and X4 commands.)
8	NO ANSWER	There was no answer-back tone. (Either the call was not answered, or a human being answered.)
9	(ABORTED)	An operator pressed any key to abort a D (Dial) or A (Answer) command

Default

Table 6: Result Code Format Command Options

Command	Meaning
V0	Sends short result codes (numeric)
V1	Sends long result codes (text)

Xn (Extended Result Codes)

Selects the extended result code format sent to the workstation. Table 7 lists extended result codes command options.

When the modem is set to ignore dial tone, it waits for the time delay specified in register S6 and dials with or without a dial tone. (See "S6 (Wait Before Dialing)," page 17, for information on register S6.)

See also the Vn command (Result Code Format), above, which selects short or long form result codes.

Default

**Table 7: Extended Result Codes Command Options**
Command	Meaning
X0	Sends the CONNECT result code when a connection is established. The modem ignores dial tones and busy signals.
X1	Sends a verbose connect message¹ when a connection is established. The modem ignores dial tones and busy signals.
X2	Sends a verbose connect message1 when a connection is established. The modem sends a NO DIALTONE result code if a dial tone is not detected within 5 seconds of a dial attempt. The modem ignores busy signals.
X3	Sends a verbose connect message1 when a connection is established. The modem sends a BUSY result code if a busy signal is detected. The modem ignores the dial tone.
X4	Sends a verbose connect message1 when a connection is established. The modem sends a NO DIALTONE result code if a dial tone is not detected within 5 seconds of a dial attempt. The modem sends a BUSY result code if a busy signal is detected.

¹ The connect message includes the rate in bits per second of the connection, the protocol used, and the compression. For example, a connect message might read "CONNECT 33600 /V.42/V.42bis".

Z (Reset)

Hangs up the telephone line, clears the modem, and restores the factory default settings.

Percent Command Set

This section describes modem commands that begin with a percent (%) character.

%R (Verbose Display of the Modem Configuration)

Displays (reads) the modem configuration, showing the contents of modem S registers first as a list of values in hexadecimal and decimal format (the Configuration Summary), and then as a more detailed table with register settings in decimal (in the Value column) and descriptions of the registers. Press Q to stop the display. This is a sample of the output resulting from the %R command:

AT%R
Cisco MICA Hex Modem Module Configuration
CONFIGURATION SUMMARY
 REG =  HEX/DEC   REG =  HEX/DEC   REG =  HEX/DEC   REG =  HEX/DEC
 S00 = 0001/1     S13 = 0000/0     S26 = 0000/0     S39 = 0007/7   
 S01 = 0000/0     S14 = 0001/1     S27 = 0000/0     S40 = 0000/0   
 S02 = 002B/43    S15 = 0001/1     S28 = 0000/0     S41 = 002B/43  
 S03 = 000D/13    S16 = 0032/50    S29 = 0000/0     S42 = 000D/13  
 S04 = 000A/10    S17 = 0064/100   S30 = 8340/33600 S43 = 000A/10  
 S05 = 0008/8     S18 = 000D/13    S31 = 012C/300   S44 = 0008/8   
 S06 = 0002/2     S19 = 000C/12    S32 = 0002/2     S45 = 0002/2   
 S07 = 0028/40    S20 = 0100/256   S33 = 01F4/500   S46 = 0028/40  
 S08 = 0002/2     S21 = 0003/3     S34 = 03E8/1000  S47 = 0002/2   
 S09 = 013D/317   S22 = 0001/1     S35 = 0032/50    S48 = 013D/317 
 S10 = 000E/14    S23 = 0001/1     S36 = 0014/20    S49 = 000E/14  
 S11 = 0000/0     S24 = 0001/1     S37 = 0028/40
 S12 = 0008/8     S25 = 0000/0     S38 = 000E/14
Reg  Value   Description
---  -----   -----------
S0  [    1]  Automatic Answer
S2  [   43]  Escape Code Character
S3  [   13]  Carriage Return Character
S4  [   10]  Line Feed Character
S5  [    8]  Backspace Character
S6  [    2]  Pause Before Blind Dialing (seconds)
S7  [   40]  Connect Complete Timeout (seconds)
S8  [    2]  Comma Dial Modifier Time (seconds)
Strike a key when ready (Q to QUIT)
S9  [  317]  Bit-Mapped Register
               0 = Command echo
                   0 = E0 - No echo
                   1 = E1 - Echo
               1,2 = Result codes
                   0 = Q0 - Output result code
                   1 = Q1 - No result codes
                   2 = Q2 - No result codes in Answer mode
               3 = Result type
                   0 = V0 - Short form
                   1 = V1 - Long form
               4,5 = Data Terminal Ready
                   0 = &D0 - Ignore DTR
                   1 = &D1 - Modem enters command state
                   2 = &D2 - Modem goes on hook
                   3 = &D3 - Modem is reset
               6,7,8 = CONNECT Result Code & Call Progress
                          Text Busy NoDT
                   0 = X0 - N    N    N
                   1 = X1 - Y    N    N
                   2 = X2 - Y    N    Y
                   3 = X3 - Y    Y    N
                   4 = X4 - Y    Y    Y
S10 [   14]  Automatic Disconnect Delay
S11 [    0]  Link Initiate Action
               0 = Answer
               1 = Originate
S12 [    8]  Number of async data bits
              - NO PROTOCOL ASYNC MODE ONLY -
               7 = 7 data bits
               8 = 8 data bits
S13 [    0]  Parity Configuration
              - NO PROTOCOL ASYNC MODE ONLY -
               0 = No parity
               1 = Even parity
               2 = Odd parity
               3 = Space parity
               4 = Mark parity
Strike a key when ready (Q to QUIT)
S14 [    1]  Stop Bit Configuration
              - NO PROTOCOL ASYNC MODE ONLY -
               1 = 1 stop bit
               2 = 2 stop bits
S15 [    1]  V.42 detect phase
               0 = Disabled
               1 = Enabled
S16 [   50]  EC Autodetect Time-out (100 msec)
S17 [  100]  EC Negotiate Time-out (100 msec)
S18 [   13]  EC Fallback Character
S19 [   12]  EC Retransmission Limit
S20 [  256]  EC max packet length (64..1024)
               max window = 8192/<length>
S21 [    3]  Data Compression
               0 = Disabled
               1 = V.42bis
               2 = MNP5
               3 = MNP5 or V.42bis
S22 [    1]  ARA Error Correction
               0 = Disabled
               1 = Answer any ARA, don't originate
               2 = Originate ARA1.0, answer any
               3 = Originate ARA2.0, answer any
S23 [    1]  V.42 (LAPM) Error Correction
               0 = Disabled
               1 = Enabled
S24 [    1]  MNP (2-4) Error Correction
               0 = Disabled
               1 = Enabled
Strike a key when ready (Q to QUIT)
S25 [    0]  Fallback Link Protocol
               0 = Async data mode
               1 = Sync data mode
               2 = Hangup
S27 [    0]  Calling Tone
               0 = Disabled
               1 = Enabled
S28 [    0]  Guard Tone
               0 = Disabled
               1 = Enabled
S29 [    0]  Modulation Standards
               0 = V.34+ Automode, with terbo
               1 = V.34+ Automode, no terbo
               2 = V.32 terbo Automode
               3 = V.32bis Automode
               4 = V.22bis Automode
S30 [33600]  Maximum Connect Rate
               (75 to 33600 bps)
S31 [  300]  Minimum Connect Rate
               (75 to 33600 bps)
S32 [    2]  Signal Quality Threshold
               0 = No action on bit errors
               1 = Bers >= 1:100
               2 = Bers >= 1:1000
               3 = Bers >= 1:10000
               4 = Bers >= 1:100000
               5 = Bers >= 1:1000000
S33 [  500]  Speed change squelch time (1 msec)
S34 [ 1000]  Fall-forward timer (10 msec)
S35 [   50]  Fallback timer (10 msec)
S36 [   20]  Terminate timeout (1 sec)
S37 [   40]  S7: Delay til data mode (1 sec)
Strike a key when ready (Q to QUIT)
S38 [   14]  Lost carrier hangup timer (100 msec)
S39 [    7]  Transmit Level Setting
               0:-6dBm 4:-10dBm  8:-14dBm 12:-18dBm
               1:-7dBm 5:-11dBm  9:-15dBm 13:-19dBm
               2:-8dBm 6:-12dBm 10:-16dBm 14:-20dBm
               3:-9dBm 7:-13dBm 11:-17dBm 15:-21dBm
S40 [    4]  Consecutive retrain disconnect threshold
S41 [    5]  V.34 Maximum Symbol Rate
S42 [    0]  V.34 Minimum Symbol Rate
S43 [    2]  V.34 Carrier Frequency
S44 [   11]  V.34 Preemphasis Filter Selection
S45 [    0]  Signaling type for use on T1/R2 trunks
               0 = Null Signaling
               1 = MF Signaling
               2 = DTMF Signaling
               3 = Low Band R2 Signaling
               4 = Hi Band R2 Signaling
S46 [    0]  Call progress detection (bit mapped)
               0 = Disabled
               1 = Dialtone
               2 = Ringback
               4 = Busy
S47 [    2]  Hayes escape detector
               0 = Disabled
               1 = Enabled
               2 = Enabled only in Originate mode
S48 [    1]  AT command processor
               0 = Disabled
               1 = Enabled
S49 [    0]  Call Setup delay (100 msec)
OK

Ampersand Command Set

This section describes modem commands that begin with an ampersand (&) character.

&Cn (Serial Port DCD Control)

This command is provided for compatibility; it has no effect. (The modem responds OK but takes no action.) Note, however, that n must be 0 or 1. The modem range-checks the value of n, so if you enter something other than 0 or 1, the modem returns an error.

Note It is likely that functionality will be added to this command in a future release of the MICA firmware.

&Dn (DTR Control)

Specifies the modem action when data terminal ready (DTR) transitions off. Table 8 lists DTR control command options.

Note It is likely that functionality will be added to this command in a future release of the MICA firmware.

Default

&D3

Table 8: DTR Control Command Options

Command	Meaning
&D0	DTR changes do not reset configuration. This option is provided for compatibility.
&D1	DTR changes do not reset configuration. This option is provided for compatibility.
&D2	The modem disconnects on detecting on-to-off transition of DTR, then enters command state. DTR changes do not reset configuration.
&D3	The modem disconnects on detecting on-to-off transition of DTR, then enters command state. The configuration is reset.

&F (Restore Factory Defaults)

Hangs up the telephone line, clears the modem, and restores the factory default configuration. This command can also be entered as &F0.

&Tn (Diagnostic Test Mode)

This command is provided for compatibility; it has no effect. (The modem responds OK but takes no action.)

Backslash Command Set

This section describes modem commands that begin with a backslash (\) character.

\S (Verbose Display of Current Modem Statistics)

Displays a list of current link statistics, including the elapsed connect time, counts of bytes in and out, and IP and EC packets sent and received. Press any key to display the next screen. Press Q to cancel the display. If a number is too large to be displayed, its left-most digit appears as a hash mark (#).

This is a sample of the output resulting from the /S command:

AT\S
Cisco MICA Hex Modem Link Statistics
Host interface protocol (IP)       RAW
Data compression protocol          V.42bis
Line interface protocol (EC)       V.42 (LAP-M)
Line modulation standard           V.34+
Line transfer rates                33600 bps TX and 33600 bps RX
The modem has been connected       0 days, 0:00:04
Line quality                       7
Bytes sent to host               436 Bytes received from host         12
Bytes received from line           0 Bytes sent to line                0
IP packets received from line      0 IP packets sent to line           0
IP packets received errored        0 IP packets aborted                0
EC frames received from line       3 EC frames sent to line            3
EC NAKs received from line         0 EC NAKs sent to line              0
EC frames retransmitted            0 EC ACK timeouts                   0
Last disconnect reason        0xE006
                         .Tx. / .Rx.
Carrier Frequency (Hz)   1959 / 1959
Symbol rate (baud/sec)   3429 / 3429
Trellis code               16 /   16
Non-linear encoding        On /   On
Precoding                 Off /  Off
Constellation shaping      On /   On
Preemphasis index           0 /    0
RX level (dBm)            -13 /   -9
TX level reduction (dBm)    0 /    0
SNR (dB)                 33
Far-end echo (dBm)       -97
Round-trip delay (ms)    3
Frequency offset (Hz)    -0.5
Phase roll freq (Hz)     0.0
Phase jitter freq (Hz)   0.0
Phase jitter level (deg) 0
OK

Modem S Register Summary

The modem saves configuration settings in S registers that are similar to Hayes Smartmodem 2400 registers. Each register controls a single modem function or is bit-mapped to control several functions. (For information on how to use bit-mapped registers, see "Bit-Mapped Registers," page 15.)

S Register Commands

This section describes commands that display and change register values.

Read All Registers

The %R command displays the contents of all S registers. The register contents are displayed as a table in decimal and hexadecimal format.

Point to a New Reference Register

The Sn command sets the modem register pointer to register n. Register n then becomes the reference register for subsequent register commands.

Read a Configuration Register

The Sn? command displays the contents of register n, in decimal format only. Register n becomes the reference register.

Change the Value of a Register

The Sn=x command changes the value of register n to x, where x is a decimal value. The Sn=>y command changes the value of register n to y, where y is a hexadecimal value. In either case, register n becomes the reference register.

Display the Value of the Reference Register

The ? command displays the value of the last S register referenced in a read, change, or point command.

Change the Value of the Reference Register

The =x command changes the value of the last S register referenced to x, where x is a decimal number. The =>y command changes the value of the last S register referenced to y, where y is a hexadecimal number.

Bit-Mapped Registers

Some S registers are bit-mapped so that they control several functions. (For example, see S9 and S46.) For each bit-mapped register, the section "S Register Descriptions" includes a table like the one below that lists register values and describes the feature associated with each value. To turn on a feature, set the register to the appropriate value. To turn on two or more features, add their values and set the register to the total.

For example, suppose you want to set the register described in Table 9 to disable quick retrains (value = 0), no result codes in answer mode (value = 4), and disable 8S-2D trellis encoding (value = 8). Total the values: 0 + 4 + 8 = 12, then set the register to 12. Note that this sample register is used for purposes of illustration and does not correspond to any actual MICA register.

**Table 9: Sample Bit-Mapped Register**
Bit	Meaning	Values
0	Quick retrains	0 Enable quick retrains 1 Disable quick retrains
1, 2	Result codes	0 Result codes 2 No result codes 4 No result codes in answer mode
3, 4, 5, 6, 7	Trellis encoding	0 Enable trellis encoding 8 Disable 8S-2D trellis encoding 16 Disable 16S-4D trellis encoding 32 Disable 32S-4D trellis encoding 64 Disable 64S-4D trellis encoding 128 Disable nonlinear coding

S Register Descriptions

This section describes the purpose and format of each S register.

Note The functions of the S registers may change from one MICA firmware release to another.

S0 (Automatic Answer in Seconds)

Specifies the interval in seconds between receiving notification of an incoming call and answering the call.

Range

0 (Answer immediately)
1 to 255 (Wait 1 to 255 seconds before answering)

Default

0 (Answer immediately)

S1 (Unused)

S2 (Escape Code Character )

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

Note Two registers, S2 and S47, control the escape code. To enable the escape code, you must set S2 to a value in the range 0 to 127, and you must set S47 to enabled (1 or 2). (See "S47 (Hayes +++ Escape Detection)," page 33.) To disable the escape code, you can either set S2 to 128 or higher, or set S47 to disabled (0).

Range

0 to 255 (ASCII decimal)

Default

43 (+)

S3 (Carriage Return Character)

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

Range

0 to 127 (ASCII decimal)

Default

13 (carriage return)

S4 (Line Feed Character)

Specifies the ASCII value for the line feed (LF) character. The linefeed character follows a carriage return at the end of long-form result codes. Short-form result codes are sent without line feeds. (See "Vn (Result Code Format)," page 7, for descriptions of long-form and short-form result codes.)

Range

0 to 127 (ASCII decimal)

Default

10 (Line feed)

S5 (Backspace Character )

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

Range

0 to 127 (ASCII decimal)

Default

8 (Backspace)

S6 (Wait Before Dialing )

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.

Range

2 to 255 seconds

Default

2 seconds

S7 (Wait for Carrier After Dial)

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

Carrier from the remote modem in originate or answer mode
Ringback, only 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.

Range

0 to 255 seconds

Default

40 seconds

S8 (Pause Time for Comma Dial Modifier)

Specifies the time the modem waits when the pause dial modifier (,) is used in a dial string.

Note Register S8 and the comma dial modifier are provided for compatibility with modems that use these features. They do not function in MICA devices.

Range

0 to 255 seconds

Default

S9 (Modem Settings)

The modem uses S9 to store the values that you set with the E, Q, V, &D, and X commands.

Note We recommend that, wherever possible, you use the E, Q, V, &D, and X commands to change S9 register values.

S9 is a bit-mapped register. See "Bit-Mapped Registers," page 15, for information on how to set bit-mapped registers. Table 10 defines the bits in S9, with the default values shown in bold.

**Table 10: S9 Values**
Bit	Meaning	Values (Default Is in Bold)
0	Command echo	0 No echo (E0) 1 Echo (E1)
1, 2	Result codes	0 Result codes (Q0) 2 No result codes (Q1) 4 No result codes in answer mode (Q2)
3	Result type	0 Short form (V0) 8 Long form (V1)
4, 5	Action on loss of Data terminal ready (DTR) signal	0 Ignore DTR (&D0) 16 Modem enters command state (&D1) 32 Sets modem on hook (&D2) 48 Resets modem (&D3)
6, 7, 8	Connect result code format and call progress	0 Sends connect result code, ignores dial tones and busy signals (X0) 64 Sends verbose connect result code, ignores dial tones and busy signals (X1) 128 Sends verbose connect and no dial tone result codes, ignores busy signals (X2) 192 Sends verbose connect and busy result codes, ignores dial tone (X3) 256 Sends verbose connect, no dial tone, and busy result codes (X4)

Range

0 to 317

Default

317

S10 (Delay for Hangup After Carrier Loss )

Specifies the time the modem waits before hanging up after loss of carrier, allowing for a temporary loss. Both modems 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. After disconnecting, the modem waits a minimum of 5 seconds before going off-hook in originate mode.

Register S10 is linked to register S38 so that the two registers share a single value. Changing the value of S10 changes the value of S38, and changing S38 changes S10.

Range

0 to 255 (0.1-second increments)

Default

14 (1.4 seconds)

S11 (Link Initiate Action)

If the modem is idle (in escape or command state) and receives the ATO (on line) command, it originates or answers calls, based on the contents of this register.

Range

0 (Answer)
1 (Originate)

Default

0 (Answer)

S12 (Number of Async Data Bits)

Specifies the number of asynchronous data bits for the call.

Note If error correction is successfully negotiated (see registers S22, S23, and S24), the modem always uses 8-bit data, regardless of how this register is set.

Range

7 or 8

Default

S13 (Parity Configuration)

Specifies the character parity for the call.

Note If error correction is successfully negotiated (see registers S15, S22, S23, and S24), parity is meaningless and the setting of this register has no effect.

Range

0 (No parity)
1 (Even parity)
2 (Odd parity)
3 (Space parity)
4 (Mark parity)

Default

0 (No parity)

S14 (Stop Bit Configuration)

Specifies the number of stop bits for the call.

Note If error correction is successfully negotiated (see registers S15, S22, S23, and S24), stop bits are meaningless and the setting of this register has no effect.

Range

1 or 2

Default

S15 (V.42 Detect Phase Operation)

Enables or disables V.42 detect phase, during which two modems prepare to negotiate a common error correction protocol. This register controls the originating modem's behavior only; in answering mode, detect phase is automatic. The length of the negotiation period is controlled by S16.

Note V.42 detect phase is also disabled if LAP-M error correction is disabled by setting S23 to 0. See "S23 (V.42 LAP-M Error Correction)," page 24.

Range

0 (Disable V.42 detect phase)
1 (Enable V.42 detect phase)

Default

1 (Enable V.42 detect phase)

S16 (Error Correction Autodetect Timeout)

Specifies, in 100-millisecond steps, the period for which the modem can remain in V.42 detect phase. This timeout period is used only if V.42 detect phase is enabled; see "S15 (V.42 Detect Phase Operation)," above. See "S25 (Link Protocol Fallback)," page 24, for a description of the fallback action invoked by the modem if the detect phase times out.

Range

0 (Run detect mechanism until manual intervention occurs or a pattern match is found)
1 to 255 (Run detect mechanism for 0.1 to 25.5 seconds)

Default

50 (5 seconds)

S17 (Error Correction Negotiation Timeout)

Specifies, in 100-millisecond steps, the period during which the modem can negotiate an error correction protocol. Unsuccessful negotiation results in fallback at the end of the specified time period. The fallback action is set using S25; see "S25 (Link Protocol Fallback)," page 24.

Range

0 (Wait indefinitely for protocol negotiation or manual intervention)
1 to 255 (Wait 0.1 to 25.5 seconds before unsuccessful negotiation causes fallback)

Default

100 (10 seconds)

S18 (Error Correction Fallback Character)

Specifies the ASCII value of the error correction fallback character. The partner modem can send this character three times during V.42 detect phase (during call establishment) to force the modem to stop negotiating and use the fallback option specified in S25. See "S15 (V.42 Detect Phase Operation)," page 21, and "S25 (Link Protocol Fallback)," page 24.

Range

0 to 127 (ASCII decimal)

Default

13 (carriage return)

S19 (Error Correction Retransmission Limit)

Specifies the number of successive frame retransmissions that take place before the modem disconnects.

Range

0 (Do not disconnect on excessive retransmission)
1 to 255 (This number of successive frame retransmissions causes disconnect)

Default

12 retransmissions

S20 (Error Correction Max Frame Length)

Specifies the maximum length for error correction frames (that is, for MNP, LAP-M, and ARA frames). Higher values are more efficient; lower values work better on a line with poor transmission quality.

Range

64 to 1024 octets of data

Default

256 octets

S21 (Data Compression)

Specifies the method of data compression. S21 is a bit-mapped register.

Range

0 (Data compression disabled)
1 (V.42bis)
2 (MNP5)
3 (V.42bis and MNP5--V.42bis has precedence)

Default

3 (V.42bis and MNP5--V.42bis has precedence)

S22 (ARA Error Correction Options)

Specifies the AppleTalk Remote Access error correction method.

If more than one method of error correction is enabled at each end of the connection, the modem chooses a method based on the following precedence:

LAP-M [highest precedence]
ARA
MNP
Fall back (refer to "S25 (Link Protocol Fallback)," page 24) [lowest precedence]

Range

0 (ARA1.0 and ARA2.0 disabled)
1 (ARA1.0 and ARA2.0 enabled for answer only)
2 (ARA1.0 and ARA2.0 enabled for answer, ARA1.0 enabled for call origination)
3 (ARA1.0 and ARA2.0 enabled for answer, ARA2.0 enabled for call origination)

Default

1 (ARA1.0 and ARA2.0 enabled for answer only)

S23 (V.42 LAP-M Error Correction)

Enables or disables V.42 (LAP-M) error correction.

If more than one method of error correction is enabled at each end of the connection, the modem chooses a method based on the following precedence:

LAP-M [highest precedence]
ARA
MNP
Fall back (refer to "S25 (Link Protocol Fallback)," page 24) [lowest precedence]

Range

0 (V.42 (LAP-M) disabled)
1 (V.42 (LAP-M) originate and answer enabled)

Default

1 (V.42 (LAP-M) originate and answer enabled)

S24 (MNP Error Correction)

Enables or disables MNP error correction.

If more than one method of error correction is enabled at each end of the connection, the modem chooses a method based on the following precedence:

LAP-M [highest precedence]
ARA
MNP
Fall back (refer to "S25 (Link Protocol Fallback)," page 24) [lowest precedence]

Range

0 (MNP disabled)
1 (MNP originate and answer enabled)

Default

1 (MNP originate and answer enabled)

S25 (Link Protocol Fallback)

If either V.42 detect phase or error correction negotiation phase (see S15, S16, and S17) ends in failure to agree on an error correction protocol, the modem takes the fallback action specified in this register. The partner modem can also force this modem to fall back using the character specified in S18. In asynchronous framing mode (0), the modem uses the settings of S12, S13, and S14. For more information on V.42 detect phase, see "S15 (V.42 Detect Phase Operation)," page 21, "S16 (Error Correction Autodetect Timeout)," page 21, "S17 (Error Correction Negotiation Timeout)," page 22, and "S18 (Error Correction Fallback Character)," page 22.

Range

0 (Enter asynchronous framing mode (start/stop/parity))
1 (Enter synchronous framing mode (raw 8 bits to DSP))
2 (Disconnect)

Default

0 (Enter asynchronous framing mode (start/stop/parity))

S26 (DSP Processor MVIP TDM Slice)

Assigns a time-division multiplexing (TDM) pair to a digital signal processor (DSP) on the modem card. There are three DSPs per modem card, and each processor is assigned one TDM pair.

Note The value of this register is set automatically to match a value stored elsewhere. Changing the value has no effect on the operation of the modem. Cisco recommends that you not change the value of this register; the value is maintained for diagnostic purposes.

Range

0 to 15

Default

None

S27 (Calling Tone)

Enables or disables the V.25 optional calling tone, a 700-Hz signal that allows the called party to determine whether the calling device is a modem. Some phone systems outside the United States and Canada require a modem to send a calling tone when it originates a connection.

Range

0 (Calling tone disabled)
1 (Send calling tone)

Default

0 (Calling tone disabled)

S28 (Guard Tone)

Enables or disables the 1800-Hz guard tone in V.22 and V.22bis modes. Some phone systems outside the United States and Canada require a modem to send a guard tone.

Range

0 (Guard tone disabled)
1 (Use guard tone (V.22 and V.22bis only))

Default

0 (Guard tone disabled)

S29 (Modem Standard)

Specifies the modulation standards to be used. When negotiating a connection with another modem, the modem tries the standards in the order listed below. For example, if S29 is set to 0, the modem first tries to negotiate a connection based on V.34+, then V.34, then V.32 terbo, and so on. If both modems are MICA, they will at a minimum be able to agree on one of the standards in range 4. If one modem is not MICA, the modems may fail to negotiate a standard and disconnect.

Range

Value	Modulation Standards
0	V.34+, V.34 V.32 terbo, V.32 bis, V.32 V.22 bis, V.22 BELL212 V.23 V.21 BELL103
1	V.34+, V.34 V.32 bis, V.32 V.22 bis, V.22 BELL212 V.23 V.21 BELL103
2	V.32 terbo, V.32 bis, V.32 V.22 bis, V.22 BELL212 V.23 V.21 BELL103
3	V.32 bis, V.32 V.22 bis, V.22 BELL212 V.23 V.21 BELL103
4	V.22 bis, V.22 BELL212 V.23 V.21 BELL103

Default

S30 (Maximum Connect Rate)

Maximum rate at which the modem will pass data, in bits per second. If this modem's range of connect rates does not overlap with the other modem's range (that is, if one modem's maximum connect rate is lower than the other modem's minimum connect rate (see S31)), a connection cannot be established and the modems disconnect.

Range

75 to 33600 bps

Default

33600 bps

S31 (Minimum Connect Rate)

Minimum rate at which the modem will pass data, in bits per second. If this modem's range of connect rates does not overlap with the other modem's range (that is, if one modem's maximum connect rate (see S30) is lower than the other modem's minimum connect rate), a connection cannot be established and the modems disconnect.

Range

75 to 33,600 bps

Default

300 bps

S32 (Signal Quality Threshold)

Specifies the minimum bit error rate at which the modem initiates recovery, and below which the modem considers the line to be good. Recovery consists of a retrain or of falling back to a lower data rate, depending on the modulation standard currently in use.

Range

0 (No action on bit errors)
1 (Bit error rates of at least 1 in 100 cause recovery)
2 (Bit error rates of at least 1 in 1,000 cause recovery)
3 (Bit error rates of at least 1 in 10,000 cause recovery)
4 (Bit error rates of at least 1 in 100,000 cause recovery)
5 (Bit error rates of at least 1 in 1,000,000 cause recovery)

Default

2 (Bit error rates of at least 1 in 1,000 cause recovery)

S33 (Speed Change Squelch Timer)

Specifies, in milliseconds, the time to delay after a speed shift before another speed shift is allowed.

Range

0 to 65535 (maximum value is about 1 minute)

Default

500 (0.5 second)

S34 (Fall-forward Timer)

The elapsed time, in 10-millisecond increments, during which signal quality is consistently good, that the modem waits before increasing transmission speed. To set signal quality, see "S32 (Signal Quality Threshold)," page 28.

Range

0 (Fall-forward disabled)
1 to 65535 (0.01 to 655.35 seconds before speed increase; maximum is almost 11 minutes)

Default

1000 (10 seconds)

S35 (Fallback Timer)

The elapsed time, in 10-millisecond increments, during which signal quality is consistently poor, that the modem waits before decreasing transmission speed. To set signal quality, see "S32 (Signal Quality Threshold)," page 28.

Range

0 (Fallback disabled)
1 to 65535 (0.01 to 655.35 seconds before fallback)

Default

50 (0.5 second)

S36 (Terminate Timeout)

Specifies, in seconds, the maximum time to delay after a host disconnect request before forcing the link to disconnect. (The disconnect request can be a drop in the DTR signal, an ATH (hang up) command, or an internal MICA message.) During this period, the modem sends buffered data and then clears the link.

Range

0 to 255 seconds

Default

20 seconds

S37 (Wait for Carrier After Dial)

Register S37 is linked to register S7 so that the two registers share a single value. Changing the value of S37 changes S7, and changing S7 changes S37. For a description of the function of the two registers, see "S7 (Wait for Carrier After Dial)," page 17.

S38 (Delay for Hangup After Carrier Loss)

Register S38 is linked to register S10 so that the two register share a single value. Changing the value of S38 changes S10, and changing S10 changes S38. For a description of the function of the two registers, see "S10 (Delay for Hangup After Carrier Loss)," page 19.

S39 (Transmit Level Setting)

Specifies the decibel level the modem uses for transmissions.

Range

Value	Decibel level
0	-6 dBm
1	-7 dBm
2	-8 dBm
3	-9 dBm
4	-10 dBm
5	-11 dBm
6	-12 dBm
7	-13 dBm
8	-14 dBm
9	-15 dBm
10	-16 dBm
11	-17 dBm
12	-18 dBm
13	-19 dBm
14	-20 dBm
15	-21 dBm

Default

7 (-13 dBm)

S40 (Consecutive Retrain Disconnect Threshold)

After this number of successive failed retrains, the modem disconnects. (If the modem loses DSP synchronization with its partner, it can try to regain synchronization with a retrain.)

Range

0 (Never disconnect due to failed retrains)
1 to 255 (Disconnect after this number of failed retrains)

Default

4 retrains

S41 (V.34 Maximum Symbol Rate)

Specifies the maximum symbol (baud) rate that pertains when the modem is using V.34 modulation. (To select the modulation standard, see "S29 (Modem Standard)," page 26.)

Range

0 (2400 baud)
1 (2743 baud)
2 (2800 baud)
3 (3000 baud)
4 (3200 baud)
5 (3429 baud)

Default

5 (3429 baud)

S42 (V.34 Minimum Symbol Rate)

Specifies the minimum symbol (baud) rate that pertains when the modem is using V.34 modulation. (To select the modulation standard, see "S29 (Modem Standard)," page 26.)

Range

0 (2400 baud)
1 (2743 baud)
2 (2800 baud)
3 (3000 baud)
4 (3200 baud)
5 (3429 baud)

Default

0 (2400 baud)

S43 (V.34 Carrier Frequency)

Specifies the carrier frequency that pertains when the modem is using V.34 modulation. (To change the modulation standard, see "S29 (Modem Standard)," page 26.)

Range

0 (Low carrier)
1 (High carrier)
2 (Automatic carrier selection)

Default

2 (Automatic carrier selection)

S44 (V.34 Pre-emphasis Filter Selection)

Specifies the filter to use on the transmit signal when the modem is using V.34 modulation. (To select the modulation standard, see "S29 (Modem Standard)," page 26.) The default setting, 11, selects a filter automatically based on line impairments and conditions. Settings 0 to 10 select fixed pre-emphasis filters without regard for line impairments and conditions. Cisco recommends that you leave this register set to the default value, 11 (automatic selection), unless you are advised otherwise by a Cisco representative. For more information on pre-emphasis filter selection, see CCITT Recommendation V.34.

Range

0 to 10 (Fixed filters)
11 (Automatic pre-emphasis selection)

Default

11 (Automatic pre-emphasis selection)

S45 (Signaling Type)

Specifies the type of transmit and receive signaling the modem uses on T1/R2 trunks.

Range

0 (Null signaling)
1 (MF signaling)
2 (DTMF signaling)
3 (Low-band R2 signaling)
4 (High-band R2 signaling)

Default

0 (Null signaling)

S46 (Call Progress Tone Detection)

Determines whether the modem detects dial tones, ring-back tones, and busy signals emitted by other devices during call establishment. S46 is a bit-mapped register. The bits are defined in Table 11.

**Table 11: Call Progress Tone Detection**
Bit	Meaning	Values
0	Dial tone	0 Ignore dial tone 1 Detect dial tone
1	Ring back	0 Ignore ring back 2 Detect ring back
2	Busy signal	0 Ignore busy signal 4 Detect busy signal

Range

0 to 7

Default

0 (No tone detection)

S47 (Hayes +++ Escape Detection)

Enables or disables detection of the +++ command that puts the modem in escape mode. Escape mode enables you to enter commands while this modem is connected to another modem.

Range

0 (Disabled)
1 (Enabled)
2 (Enabled in originate mode only)

Default

2 (Enabled in originate mode only)

S48 (AT Command Processor)

Enables or disables the AT command processor.

Range

0 (Disabled)
1 (Enabled)

Default

1 (Enabled)

S49 (Call Setup Delay)

Specifies, in 100-msec increments, the time for which the modem waits before initiating a new link.

Range

0 (No delay before link initiation)
1 to 255 (Wait 0.1 to 25.5 seconds)

Default

0 (No delay before link initiation)

Cisco Connection Online

Cisco Connection Online (CCO) is Cisco Systems' primary, real-time support channel. Maintenance customers and partners can self-register on CCO to obtain additional information and services.

Available 24 hours a day, 7 days a week, CCO provides a wealth of standard and value-added services to Cisco's customers and business partners. CCO services include product information, product documentation, software updates, release notes, technical tips, the Bug Navigator, configuration notes, brochures, descriptions of service offerings, and download access to public and authorized files.

CCO serves a wide variety of users through two interfaces that are updated and enhanced simultaneously: a character-based version and a multimedia version that resides on the World Wide Web (WWW). The character-based CCO supports Zmodem, Kermit, Xmodem, FTP, and Internet e-mail, and it is excellent for quick access to information over lower bandwidths. The WWW version of CCO provides richly formatted documents with photographs, figures, graphics, and video, as well as hyperlinks to related information.

You can access CCO in the following ways:

WWW: http://www.cisco.com
WWW: http://www-europe.cisco.com
WWW: http://www-china.cisco.com
Telnet: cco.cisco.com
Modem: From North America, 408 526-8070; from Europe, 33 1 64 46 40 82. Use the following terminal settings: VT100 emulation; databits: 8; parity: none; stop bits: 1; and connection rates up to 28.8 kbps.

For a copy of CCO's Frequently Asked Questions (FAQ), contact cco-help@cisco.com. For additional information, contact cco-team@cisco.com.

Note If you are a network administrator and need personal technical assistance with a Cisco product that is under warranty or covered by a maintenance contract, contact Cisco's Technical Assistance Center (TAC) at 800 553-2447, 408 526-7209, or tac@cisco.com. To obtain general information about Cisco Systems, Cisco products, or upgrades, contact 800 553-6387, 408 526-7208, or cs-rep@cisco.com.

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