Cisco AS5400 Series Universal Gateways

Table Of Contents

AT Command Set and Register Summary for NextPort Universal Digital Signal Processor Platforms

Entering AT Commands

Alphabetic Command Set

A/ (Repeat Last Command)

A (Answer)

AT (Attention)

D {dial string} (Dial)

D {t} {m} {dial string}

En (Command Echo)

H or H0 (Hang Up)

In (Inquiry)

Ln (Monitor Speaker Loudness)

Mn (Monitor Speaker Mode)

O (Online from Escape Mode)

P (Pulse Dial)

Qn (Quiet)

Sn (Point to a New Configuration Register)

Sn? (Read Configuration Register)

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

T (Tone Dial)

Vn (Result Code Format)

Xn (Extended Result Codes)

Z (Reset)

Percent Command Set

%R (Verbose Display of the Modem Configuration)

Ampersand Command Set

&Cn (Serial Port DCD Control)

&Dn (DTR Control)

&Fn (Restore Factory Defaults)

&Tn (Diagnostic Test Mode)

&Vn (Display Modem Information)

+F Command Set

+FCLASS (Service Class)

FAX Class 2 Action Commands

FAX Class 2 Parameter Commands

Backslash Command Set

\B (Transmit a Break)

\Qn (Flow Control)

\S (Verbose Display of Current Modem Statistics)

Modem S Register Summary

S Register Commands

Read All Registers

Read a Configuration Register

Point to a New Reference Register

Change the Value of a Register

Display the Value of the Reference Register

Change the Value of the Reference Register

Bit-Mapped Registers

S Register Descriptions

S0 (Automatic Answer in Seconds)

S1 (Unused)

S2 (Escape Code Character)

S3 (Carriage Return Character)

S4 (Line Feed Character)

S5 (Backspace Character)

S6 (Wait Before Dialing)

S7 (Wait for Carrier After Dial)

S8 (Comma Dial Modifier)

S9 (Modem Settings)

S10 (Delay for Hang-up After Carrier Loss)

S11 (Link Initiate Action)

S12 (Number of Async Data Bits)

S13 (Parity Configuration)

S14 (Stop Bit Configuration)

S15 (V.42 Detect Phase Operation)

S16 (Error Correction Autodetect Timeout)

S17 (Error Correction Negotiation Timeout)

S18 (Error Correction Fallback Character)

S19 (Error Correction Retransmission Limit)

S20 (Error Correction Max Frame Length)

S21 (Data Compression)

S22 (ARA Error Correction Options)

S23 (V.42 LAP-Modem Error Correction)

S24 (Microcom Network Protocol Error Correction)

S25 (Link Protocol Fallback)

S27 (Calling Tone)

S28 (Guard Tone)

S29 (Modulation Standard)

Digital and Analog Modulations

Effect of FSK on Framing

S30 (Maximum Connect Rate)

S31 (Minimum Connect Rate)

S32 (Signal Quality Threshold)

S33 (Speed Change Squelch Timer)

S34 (Fall-forward Timer)

S35 (Fallback Timer)

S36 (Terminate Timeout)

S37 (Wait for Carrier After Dial)

S38 (Delay for Hang-up After Carrier Loss)

S39 (Transmit Level Setting)

S40 (Consecutive Retrain Disconnect Threshold)

S41 (V.34 Maximum Symbol Rate)

S42 (V.34 Minimum Symbol Rate)

S43 (V.34 Carrier Frequency)

S44 (V.34 Preemphasis Filter Selection)

S47 (Hayes +++ Escape Detection)

S48 (AT Command Processor)

S50 (Maximum PCM Connect Rate)

S51 (Minimum PCM Connect Rate)

S52 (Digital Pad Compensation)

S53 (V.8bis Capability)

S54 (General Options)

S56 (Set Maximum V.34+ Transmit Rate)

S57 (User Rate for ISDN, V.110, V.120, and Clear Channel)

S59 (V.90 Transmit Level Setting)

S61 (Microcom Network Protocol 10-EC)

S62 (V.92 Modem on Hold Exchange)

S63 (Quick Connect Exchange)

S64 (Link Standard)

S65 (V.44 Maximum TX Codewords)

S66 (V.44 Maximum RX Codewords)

S67 (V.44 Maximum TX String Length)

S68 (V.44 Maximum RX String Length)

S69 (V.44 Maximum TX History Size)

S70 (V.44 Maximum RX History Size)

S75 (Answer Tone Length)

S76 (Rx Aggression Control)

S77 (Tx Aggression Control)

S78 (56K Plus)

S79 (Client Uplink Rate)

Transmit Level Setting Based on Country Code

Related Links

Obtaining Documentation

World Wide Web

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Ordering Documentation

Documentation Feedback

Obtaining Technical Assistance

Cisco.com

Technical Assistance Center

Cisco TAC Web Site

Cisco TAC Escalation Center

AT Command Set and Register Summary for NextPort Universal Digital Signal Processor Platforms

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May 29, 2007

This document describes modem AT commands and S-registers for Cisco NextPort universal digital signal processor (DSP) modules. NextPort is the next generation DSP used by Cisco to implement either voice, data, or fax on a given port.

To use this document, you should be familiar with digital modem theory and the use of modemcaps to change the configuration of a digital modem. For more information on digital modems and modemcaps, please refer to the Modem Management Commands document and the
Modem-Router Connection Guide.

For information about managing modems on Cisco access gateways using Cisco IOS software commands, refer to the software configuration guide for the access server in which the modems are installed.

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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 countries.

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This document contains the following sections:

•Entering AT Commands

•Alphabetic Command Set

•Percent Command Set

•Ampersand Command Set

•+F Command Set

•Backslash Command Set

•Modem S Register Summary

•S Register Descriptions

•Related Links

•Obtaining Documentation

•Obtaining Technical Assistance

Entering AT Commands

To send AT commands to the modem, you must first put the modem in AT command mode. Entering AT command mode involves a reverse Telnet procedure. The table below shows how to enter AT command mode from Cisco IOS EXEC mode using reverse Telnet.

.

Step	Command	Purpose
Step 1	> telnet ip-address line# Trying 172.0.0.1, 2001 ... Open	Open a reverse Telnet connection to the modem. In this example, 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. Use one of those numbers. The Telnet connection is open when the word Open appears.
Step 2	at OK	There is no command prompt in AT command mode. To confirm that you can enter AT commands, enter at and press Return. If you are in AT command mode, the modem returns OK.
Step 3	Ctrl-Shift-6 X # disconnect	When you have finished entering AT commands, exit AT command mode and return to privileged EXEC mode. To do so, enter Ctrl-Sh-6 X (that is, hold down the Control and Shift keys and press 6, and then release everything and press X). Enter disconnect to end the Telnet connection.

Use these guidelines when you send AT commands to a modem:

•Enter the AT prefix before all commands except A/ (Repeat Last Command) and +++ (Escape code). Commands are carried out when you press Return or Enter.

•Command lines are limited to 128 characters, not including the AT prefix and Return characters. Dial strings, however, are limited to 49 characters.

•You can enter several commands on the same command line, as long as you do not exceed the 128-character limit (see preceding item). Enter commands with no spaces or separators between them. The commands are carried out in the order in which they appear on the command line. If an individual command fails (returns ERROR), any subsequent commands on that line are not carried out.

•Certain commands work only if they are the last command on the line. Such commands include
A (answer), D (dial), H (hang up), Z (reset), and any command that takes time to execute or that does not return a result immediately.

•Spaces within AT commands are permitted anywhere except between the A and the T. For example, enter ATS0?, AT S0?, ATS 0?, but not A TS0?.

•Enter commands as either uppercase or lowercase, not mixed case.

•Enter Ctrl-C (^C) to abort a partially entered command. The modem echoes ^C.

•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 the "S5 (Backspace Character)" section.

•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. To return to the online state from any other state, enter ATO and press Return. A fresh connect message is sent.

–Escape state: Allows you to enter commands while the modem is on line. To go to escape state, enter +++ (+++ is the default escape code; see "S2 (Escape Code Character)," on page 19 for details on changing the escape code). When you enter the +++ command, pause for at least a second before and after typing it, but do not pause between characters. Do not press Return. Wait for the OK prompt before entering commands.

The escape code can be enabled and disabled; for instructions, see "S2 (Escape Code Character)," on page 19, and "S47 (Hayes +++ Escape Detection)" on page 39 .

Alphabetic Command Set

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

A/ (Repeat Last Command)

Enters the last command again. If there is no previous command, the modem displays OK. Do not enter the AT prefix before A/. You do not usually need to press Return after entering the A/ command.

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

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A (Answer)

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

AT (Attention)

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

D {dial string} (Dial)

Dials a telephone number, establishing a connection. Always make the Dial command the last (or the only) 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 the characters # and *.

The modem ignores invalid characters. If you enter dial strings longer than 49 characters, the ERROR result code appears. The following example shows the command used to dial the telephone number
1 (617) 555-1234:

D 1 (617) 555-1234

The modem ignores the spaces, parentheses, and hyphen in the examples dial string: They are not dialed and they do not count against the 49-character limit.

To cancel the Dial command, press any key, or clear the call from the router or access server.

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 the ERROR result code.

For compatibility, the modem accepts these dial modifiers but does not act on them:

•P

•T

•@ (at sign)

•! (exclamation point)

•; (semicolon)

D {t} {m} {dial string}

Initiates a call or resumes a session. In order to use the DI command, you must set register S29 to a compatible call type. The call type for ISDN is V.110 (S29 = 8). See the "S29 (Modulation Standard)" section. The Dial command must be the last command on the command line.

Valid dial types {t}. 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 the characters, # and *.

The modem (or the modem and the host) ignores invalid characters. If you enter a dial string longer than 49 characters, the modem returns the ERROR result code. The following example shows the command used to dial the telephone number 1 (617) 555-1234

DI 1 (617) 555-1234

The modem ignores the spaces, parentheses, and hyphen in the examples dial string: They are not dialed and they do not count against the 49-character limit.

To cancel the ISDN Dial command, press any key, or clear the call from the router or access server.

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

For compatibility, the modem accepts these dial modifiers but does not act on them:

•P

•T

•@ (at sign)

•! (exclamation point)

•; (semicolon)

En (Command Echo)

Configures the modem to echo commands to the workstation. The table below lists command echo options.

Default

E1

s

Command Option	Meaning
E0	Disables echoing of commands to the workstation.
E1	Enables echoing of commands to the workstation.

H or H0 (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. Lists inquiry command options.

Command Option	Meaning
I0	Displays the modem product ID code in the following format: NextPort Product ID = product code
I1	Runs a checksum on firmware and displays the result, as in the following example: NextPort code CHECKSUM is xxxxxxxx (where xxxxxxxx is a 32-bit checksum of the code)
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 the following example: Cisco NextPort Module Product Information           NextPort Product ID = product_code Country Code: country code Signaling: signaling supported revision date Modems: modems supported revision date Fax: fax modems revision date Voice Codec: voice codecs supported revision date ISDN: ISDN services supported revision date
I4	Displays one of the following lines describing the features available in the version of firmware running on the modem: Cisco NextPort Module Product Information NextPort Product ID = product_code Country Code: country code Signaling: signaling supported Modems: modems supported Fax: fax modems Voice Codec: voice codecs supported ISDN: ISDN services supported

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 the 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 the ERROR result code.

O (Online from Escape Mode)

Changes the modem to the online state (connected, or steady state) from escape mode. The modem displays a connect message. You can use the following values:

•o: 0 Go on-line from escape mode

•o: 1 Retrain without returning to online state

•o: 2 Fallback without returning to online state

•o: 3 Fall-forward without returning to online state

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. Lists quiet mode command options in the Vn command mode.

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

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Default

Q0

Command Option	Meaning
Q0	Enables output of result codes.
Q1	Disables output of result codes.
Q2	CONNECT and NO CARRIER result codes are disabled for answer mode only. All other result codes are generated normally (default)

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. If you enter a value for n that is outside the range of S register numbers, the command fails (returns ERROR). For descriptions of the S registers and a summary of commands you can use to manipulate S registers, see the "Modem S Register Summary" section. See also the "%R (Verbose Display of the Modem Configuration)" section.

Range

0 to 75. (The range is determined by the numbers of the S registers, which can change from one Cisco NextPort firmware release to the next as new S registers are added.)

Default

S0

Sn? (Read Configuration Register)

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

Range

0 to 75

Default

S0

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

Sets the contents of S register n (where n is a decimal number) to the value y. Some invalid values for y cause the command to fail (returning ERROR), even though other invalid values are accepted. For descriptions of the S registers, see the "Modem S Register Summary" section.

Range

n: 0 to 75
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. describes the result codes. lists options for the result code format command.

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

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Numeric Result Code	Long Result Code	Description
0	OK	Command accepted, ready for next command.
1	CONNECT [text]	A connection has been established. The long result code may be followed on the same line by speed and protocol information, depending on the setting of the X command. See the ""Xn (Extended Result Codes)" section.
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).
4	ERROR	Indicates one of the following: •Invalid command or checksum. •Command line exceeds 128 characters. •Dial string exceeds 49 characters.
5	NO DIALTONE	Dial tone was not detected, or in channelized T1 there was no trunk to seize.
6	BUSY	Busy (line engaged) signal or number unobtainable signal detected.)
7	NO ANSWER	There was no answer-back tone. (Either the call was not answered, or a human being answered.)
8	(ABORTED)	An operator pressed any key to abort a D (Dial) or A (Answer) command.

Default

V1

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

Xn (Extended Result Codes)

Selects the extended result code format sent to the workstation. The table lists options for the
extended result codes command.

Before dialling, the modem waits for the time delay specified in register S6. (See "S6 (Wait Before Dialing)" on page 20 for information on register S6.)

See also the previous section, "Vn (Result Code Format)." You can use the Vn command to select short or long form result codes.

Default

X4

Command Option	Meaning
X0	CONNECT result code is given upon entering online data state. Dial tone and busy detection are disabled.
X1	CONNECT result code is given upon entering online data state. Dial tone and busy detection are disabled. Sends a verbose connect message1 when a connection is established.
X2	CONNECT result code is given upon entering online data state. Dial tone detection is enabled and busy detection is disabled.
X3	CONNECT result code is given upon entering online data state. Dial tone detection is disabled and busy detection is enabled.
X4	CONNECT result code is given upon entering online data state. Dial tone and busy detection are enabled (default).

1 The connect message for X1 through X4 includes the rate in bits per second of the connection, the protocol used, and the compression type. For example, a connect message might read "CONNECT 33600 /V.42/V.42bis". (X0 sends only the result code, CONNECT.)

Z (Reset)

This command terminates the current call (if any) and resets the configuration to the saved value (this is currently the same as setting factory defaults, AT&F).

Percent Command Set

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

%R (Verbose Display of the Modem Configuration)

Reads and displays 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. Refer to the "S Register Commands" section to interrupt the output of this command.

Ampersand Command Set

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

&Cn (Serial Port DCD Control)

This command controls the data carrier detect (DCD) signal level presented to the host. 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.

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Note DCD processing is virtualized for digital modems, since there is no physical EIA-232 interface.

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&Dn (DTR Control)

Specifies the modem action when the host (DTE) data terminal ready (DTR) transitions off (as when the user session ends). DTR control command options are listed below.

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Note DTR processing is virtualized for digital modems, since there is no physical EIA-232 interface.

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Default

&D3

Command Option	Meaning
&D0 &D1 &D2	The end of a call does not reset the modem configuration. These options are provided for compatibility. These options maintain settings within a session. Thus, if you change settings, dial, hear a busy signal, and dial again, your new settings are still in effect. However, your settings may remain in effect for the next user of the modem.
&D3	The modem disconnects at the end of a call, then enters command state. The modem configuration is reset to factory defaults. To restore local settings, you must re-apply the modemcap from the Cisco IOS interface of the modem's host device. Note The modem treats the end of a connection (hang-up, call drop) as a DTR loss and resets its configuration if &D3 is set.

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Note Because the modem has no visibility of DTR virtualization, commands &D0, &D1, and &D2 operate identically (configuration not reset on return to IDLE). The &D3 command causes a configuration reset whenever the modem returns to IDLE. Because the modem does not have per-modem nonvolatile memory or a &W command, the &D3 command reset loads factory defaults (&F).

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&Fn (Restore Factory Defaults)

Hangs up the telephone line, clears the modem, and restores the factory default configuration, with several exceptions—the following values are preserved:

•Country code

•Central office signaling type (S45)

•Sticky flags (S60)

This command can also be entered as &F0. Entering 0 sets the configuration to factory defaults.

&Tn (Diagnostic Test Mode)

Tests the modem hardware. Lists modem test options.

Default

&T5

Command Option	Meaning
&T0	Ends the test in progress.
&T1	Enters local analog loopback (LAL) mode, in which the modem establishes a connection to itself and loops all user data back to the user. This helps to verify that the modem hardware is functioning properly. Note The modem must be IDLE or an ERROR result code is returned. Error correction must be turned off by setting S registers 22, 23, and 24 to zero; otherwise an ERROR result code is returned.

&Vn (Display Modem Information)

This command supports an implementation-specific method to display modem information, which can be used to present items such as modem configuration, connection statistics, and status. The output format is determined by the particular implementation and is not defined in this document. Any values for n that are not supported by the implementation should return the ERROR result.

+F Command Set

Fax Class 2 and Class 2.0 modem commands begin with the characters +F. Fax commands are accessed by software only. For more information on Class 2 commands, see the Electronic Industries Association publication Standards Proposal No. 2388, August 20, 1990, Asynchronous Facsimile DCE Control Standard. For more information on Class 2.0 commands, see the Electronic Industries Association publication EIA/TIA-592, Asynchronous Facsimile DCE Control Standard.

+FCLASS (Service Class)

The +FCLASS=n command sets the service class capabilities. When +FCLASS=0, the fax AT command set is not available and any fax AT command sent to the modem will return an ERROR message.

FAX Class 2 Action Commands

Action Command	Short Description
ATD<number>	Originate call.
AT+FDT	Transmit fax data.
AT+FET=<code>	Send post-page message.
AT+FKS	Terminate session.

FAX Class 2 Parameter Commands

Command	Capabilities	Short Description
AT+FAXERR?	0-103	Last hang-up status code
AT+FBADLIN	0	Number of consecutive bad lines for a bad page
AT+FBADMUL	0	Acceptable ratio of good/bad lines
AT+FBOR	0-3	Phase C data bit order
AT+FBUF?	-	Read only buffer status
AT+FBUG	0-1	HDLC frame contents reporting
AT+FCLASS	0, 2	Service class Note NextPort does not support Class 2.0.
AT+FCQ	0-1	Received quality checking
AT+FCR	0-1	Ability to receive
AT+FCTCRTY	0-255	Number of CTCs allowed in ECM
AT+FDCC	(0-1), (0-5), (0-4), (0-2),(0-3), (0-1), (0-1), (0-7)	Modem capabilities
AT+FDCS?	-	Read only current session parameters
AT+FDIS	(0-1), (0-5), (0-4), (0-2), (0-3),(0-1), (0-1), (0-7)	Session capabilities
AT+FDFFC	0	Check and convert compression formats
AT+FECM	0	Ability to do error correction
AT+FLID	(20), (32-127)	Local ID
AT+FLNFC	0	Check and convert length mismatches
AT+FLPL	0	Document available for polling
AT+FMDL?	-	Read only modem ID
AT+FMFR?	-	Read only manufacturer ID
AT+FMINSP	(0-5)	Minimum phase C data transfer speed
AT+FPHCTO	(0-255)	Phase C timeout
AT+FREV?	-	Read only revision ID
AT+FRBC	0	Receive block size
AT+FREL	0	EOL alignment
AT+FSPL	0	Request to poll
AT+FTBC	0	Transmit block size
AT+FVRFC	0	Check and convert resolution mismatches
AT+FWDFC	0	Check and convert width mismatches

In addition to the commands listed above, these Class 2 commands are defined in TIA/EIA SP-2388 and are supported in Cisco NextPort firmware: ATA, ATE0, ATS0=n, and ATV1.

Backslash Command Set

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

\B (Transmit a Break)

Sends a break (in async mode, a 300-millisecond break) that is nondestructive (does not cause data to be lost) and expedited (does not wait behind data that was entered before it). The break can be transmitted in LAP-M mode, MNP mode, and async mode.

For compatibility, Cisco NextPort modems accept a numeric argument immediately following the \B command, but the argument is ignored.

Default

\B

\Qn (Flow Control)

In fax mode, enables and disables flow control for the modem. Flow control command options are listed below.

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Note When the modem is not operating in fax mode, this command has no effect.

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Default

\Q0

Command Option	Meaning
\Q0	Disables flow control. Note The host can always exert buffering back-pressure, so it's not possible to completely disable flow control.
\Q1	Enables bidirectional Xon/Xoff flow control. Data transmission is stopped by an Xoff character and restarted by an Xon character. The modem generates Xon and Xoff characters at the same parity used on the serial port. The serial port responds to Xon and Xoff characters sent by the local workstation in the same way.
\Q2	Enables unidirectional CTS/RTS hardware flow control. Note Because the modem has no control of the router's virtualization of RTS and CTS, the \Q2 and \Q3 commands have no effect.
\Q3	Enables bi-directional CTS/RTS hardware flow control.
\Q4	Enables unidirectional XON/XOFF flow control. The modem serial port generates, but does not respond to, XON/XOFF flow control characters.

\S (Verbose Display of Current Modem Statistics)

Displays a detailed list of the modem 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 (#).

The following is an example of the \S verbose listing of the current statistics:

      Cisco NextPort Module Modem Link Statistics

      Host interface protocol (IP)  RAW

      Data compression protocol      V.44 both OR V.44 TX OR V.44 Rx

      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, 0:00:29

      Line quality   7

      Bytes sent to host     441     Bytes received from host                17

      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   9       EC frames sent to line  9

      EC NAKs received from line     0       EC NAKs sent to line    0

      EC frames retransmitted        0       EC ACK timeouts 0

      DC negotiated RX Codewords     2048    DC negotiated TX Codewords      2048 

      DC negotiated RX String Length 255     DC negotiated TX String Length  255 

      DC negotiated RX History Size  10240   DC negotiated TX History Size   10240 

      DC negotiated RX History Size          10240   DC negotiated TX History Size  10240 

      DC Decoder State       Transparent     DC Encoder State        Transparent 

      DC RX Compression Ratio        3.21:1  DC TX Compression Ratio 9.22:1 

      Last disconnect reason        0x0000

      Strike a key when ready (Q to QUIT)

      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

      RBS Pattern              0x#F  [PCM builds only]

      Digital Pad (dB)         0     [PCM builds only]

      Digital Pad Compensation On    [PCM builds only]

Modem S Register Summary

S registers can be set or read using in-band AT commands like reverse Telnet or modemcaps. They can also be read or set using out-of-band services such as direct interprocess communication (IPC) calls from Cisco IOS subsystems. Examples of this are call switch module (CSM) and resource pool management (RPM) commands.

Reserved S registers have no affect on the operation of any services.

All S registers can be modified with the ATSn=v command. For information on how to use bit-mapped registers, see the "Bit-Mapped Registers" section.

S Register Commands

This section describes AT commands that display or 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.

Read a Configuration Register

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

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.

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 the sections on S9 and S46.) For each bit-mapped register, the "S Register Descriptions" section includes a table like the one below that lists register values and describes the feature associated with each value. To turn on a single 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 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, and set the register to 12.

Sample Bit-Mapped Register	Meaning	Values
0	Quick retrains	0—Enable quick retrains (default) 1—Disable quick retrains
1, 2	Result codes	0—Result codes (default) 2—No result codes 4—No result codes in answer mode
3, 4, 5, 6, 7	Trellis encoding	0—Enable trellis encoding (default) 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.

S0 (Automatic Answer in Seconds)

Specifies the interval in seconds between the time the modem receives notification of an incoming call and the time the modem answers the call.

Range

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

Default

2 (Answer in two seconds)

S1 (Unused)

Register S1 is not used.

S2 (Escape Code Character)

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

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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)" on page 39 .) To disable the escape code, you can either set S2 to 128 or higher, or you can set S47 to disabled (0).

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Range

0 to 255 (ASCII decimal)
128 or higher disables the escape feature

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, CR)

S4 (Line Feed Character)

Specifies the ASCII value for the line feed (LF) character. The line feed character follows a carriage return at the end of long-form result codes. Short-form result codes are sent without line feeds. (See "Vn (Result Code Format)" on page 9 for descriptions of long-form and short-form result codes.)

Range

0 to 127 (ASCII decimal)

Default

10 (Line feed, LF)

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, BS)

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 225 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 when this modem is in originate or answer mode

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

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

Range

0 to 255 seconds

Default

60 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.

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Note Register S8 and the comma dial modifier are provided for command compatibility with modems that use these features.

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S8 (Comma Dial Modifier)

Command compatibility only.

Range

0 to 255 seconds

Default

2

S9 (Modem Settings)

Used to manipulate the bit mask settings of the E, V, &D and X AT commands. Use the %R command (Verbose display of the modem configuration) to see these values.

S9 is a bit-mapped register. See the "Bit-Mapped Registers" section for information on how to set bit-mapped registers. Table 1 Table 1 defines the bits in S9, with the default values shown in bold.

Table 1 S9 Values

Bit	Meaning	Values1
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)

1 Default values are in bold.

Range

0 to 301

Default

301 (0x12D)

S10 (Delay for Hang-up After Carrier Loss)

Specifies the time the modem waits before hanging up after loss of carrier. This waiting period allows the modem to recover from a temporary loss of carrier without breaking the connection. Modems at both ends of the connection should have the same values set. If the S10 values of the two modems are unequal, disconnection occurs when the lower value is reached. When register S10 is set