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This chapter describes how to configure operating characteristics for terminals. For a complete description of the terminal operation commands in this chapter, refer to the "Terminal Operating Characteristics Commands" chapter in the Configuration Fundamentals Command Reference. To locate documentation of other commands that appear in this chapter, use the command reference master index or search online.
To configure operating characteristics for terminals, perform any of the tasks in the following sections:
| Command | Purpose |
|---|---|
show whoami text | Display line information. |
If text is included as an argument in the command, that text is displayed as part of the additional data about the line.
The following example shows sample output of the show whoami command:
Router> show whoami Comm Server "Router", Line 0 at 0bps. Location "Second floor, West" --More-- Router>
To prevent the information from being lost, this command always displays a More prompt before returning. Press the space bar to return to the prompt.
The terminal EXEC commands enable or disable features for the current session only. You can use these commands to temporarily change terminal line settings without changing the stored configuration file.
To see a list of the commands for setting terminal parameters for the current session, use the following command in user EXEC mode:
| Command | Purpose |
|---|---|
terminal ? | List the commands for setting terminal parameters. |
The following example shows the type of output terminal ? could generate:
Router> terminal ?
autohangup Automatically hangup when last connection closes
data-character-bits Size of characters being handled
databits Set number of data bits per character
dispatch-character Define the dispatch character
dispatch-timeout Set the dispatch timer
download Put line into 'download' mode
editing Enable command line editing
escape-character Change the current line's escape character
exec-character-bits Size of characters to the command exec
flowcontrol Set the flow control
full-help Provide help to unprivileged user
help Description of the interactive help system
history Enable and control the command history function
hold-character Define the hold character
ip IP options
keymap-type Specify a keymap entry to use
lat DEC Local Area Transport (LAT) protocol-specific
configuration
length Set number of lines on a screen
no Negate a command or set its defaults
notify Inform users of output from concurrent sessions
padding Set padding for a specified output character
parity Set terminal parity
rxspeed Set the receive speed
special-character-bits Size of the escape (and other special) characters
speed Set the transmit and receive speeds
start-character Define the start character
stop-character Define the stop character
stopbits Set async line stop bits
telnet Telnet protocol-specific configuration
telnet-transparent Send a CR as a CR followed by a NULL instead of a CR
followed by a LF
terminal-type Set the terminal type
transport Define transport protocols for line
txspeed Set the transmit speeds
width Set width of the display terminal
Throughout this chapter, many terminal settings can be configured for all terminal sessions or for just the current terminal session. The commands will be in two forms. The basic form will be in line configuration mode and can be saved permanently so that all terminal sessions are affected. The terminal form of the command is entered in EXEC mode and only affects the current session.
You can configure the Cisco IOS software to save local parameters set with terminal EXEC commands between sessions. Saving local settings ensures that the parameters the user sets will remain in effect between terminal sessions. This function is useful for servers in private offices. To save local settings between sessions, use the following command in line configuration mode:
| Command | Purpose |
|---|---|
Save local settings between sessions. |
By default, user-set terminal parameters are cleared when the session ends with either the exit EXEC command, or when the interval set with the exec-timeout line configuration command has passed.
To end a session, use the following command:
| Command | Purpose |
|---|---|
quit | Use the quit EXEC command. |
Refer to the "Managing Connections and System Banners" chapter for more information on exiting sessions and closing connections.
This section explains how to change terminal and line settings both for a particular line and locally. The local settings are set with the EXEC terminal commands. They temporarily override the settings made by the system administrator and remain in effect only until you exit the system. In line configuration mode, you can set terminal operation characteristics that will be in operation for that line until the next time you change the line parameters.
The following sections describe the more common changes to the terminal and line settings:
The following sections describe the less common changes to the terminal and line settings:
You can define or modify the default key sequences to execute functions for system escape, terminal activation, disconnect, and terminal pause.
To define or change the default key sequence, use one or more of the following commands in line configuration mode:
| Command | Purpose |
|---|---|
escape-character ascii-number | Change the system escape sequence. The escape sequence indicates that the codes that follow have special meaning. The default escape sequence is Ctrl-^.1 |
activation-character ascii-number | Define a session activation sequence or character. Entering this sequence at a vacant terminal begins a terminal session. The default activation sequence is the Return key. |
disconnect-character ascii-number | Define the session disconnect sequence or character. Entering this sequence at a terminal ends the session with the router. There is no default disconnect sequence. |
hold-character ascii-number | Define the hold sequence or character that causes output to the terminal screen to pause. To continue the output, enter any character after the hold character. To use the hold character in normal communications, precede it with the escape character. There is no default sequence. |
| 1Pressing Ctrl displays a caret (^) character. The escape sequence is Ctrl-Shift-6. |
You can reinstate the default value for the escape character or activation character by using the no form of the command. For example, issuing the no escape-character line configuration command returns the escape character to Ctrl-^.
For the current terminal session, you can modify key sequences to execute functions for system escape and terminal pause. To modify these sequences, use one or more of the following commands in EXEC mode:
| Command | Purpose |
|---|---|
Change the system escape sequence for the current session. The escape sequence indicates that the codes that follow have special meaning. The default sequence is Ctrl-^. | |
terminal hold-character ascii-number | Define the hold sequence or character that causes output to the terminal screen to pause for this session. There is no default sequence. To continue the output, type any character after the hold character. To use the hold character in normal communications, precede it with the escape character. You cannot suspend output on the console terminal. |
The terminal escape-character command is useful, for example, if you have the default escape character defined for a different purpose in your keyboard file. Entering the escape character followed by the X key returns you to EXEC mode when you are connected to another computer.
The following sections discuss telnet operation characteristics tasks:
To cause the router to generate a hardware Break signal on the EIA/TIA-232 line that is associated with a reverse Telnet connection for the current line and session, use the following command in EXEC mode:
| Command | Purpose |
|---|---|
Generate a hardware Break signal on the EIA/TIA-232 line that is associated with a reverse Telnet connection for the current line and session. |
The hardware Break signal occurs when a Telnet Interrupt-Process command is received on that connection. This command can be used to control the translation of Telnet IP commands into X.25 Break indications.
This command is also a useful workaround in the following situations:
Some EIA/TIA-232 hardware devices use a hardware Break signal for various purposes. A hardware Break signal is generated when a Telnet Break command is received.
You can set the line to allow the Cisco IOS software to refuse full-duplex, remote echo connection requests from the other end. This refusal suppresses negotiation of the Telnet Remote Echo and Suppress Go Ahead options. To set the current line to refuse to negotiate full-duplex for the current session, remote echo options on incoming connections, use the following command in EXEC mode:
| Command | Purpose |
|---|---|
Set the current line to refuse to negotiate full-duplex for the current session. |
To allow the Cisco IOS software to negotiate transmission speed for the current line and session, use the following command in EXEC mode:
| Command | Purpose |
|---|---|
Allow the Cisco IOS software to negotiate transmission speed for the current line and session. |
You can match line speeds on remote systems in reverse Telnet, on host machines that connect to the network through an access server, or on a group of console lines hooked up to an access server, when disparate line speeds are in use at the local and remote ends of the connection. Line speed negotiation adheres to the Remote Flow Control option, defined in RFC 1080.
You can set lines on the access server to cause a reverse Telnet line to send a Telnet Synchronize signal when it receives a Telnet Break signal. The TCP Synchronize signal clears the data path, but interprets incoming commands. To cause the Cisco IOS software to send a Telnet Synchronize signal when it receives a Telnet Break signal on the current line and session, use the following command in EXEC mode:
| Command | Purpose |
|---|---|
Cause the Cisco IOS software to send a Telnet Synchronize signal when it receives a Telnet Break signal on the current line and session. |
The end of each line typed at the terminal is ended with a Return (CR). To cause the current terminal line to send a CR as a CR followed by a NULL instead of a CR followed by a line feed (LF), use the following command in EXEC mode:
| Command | Purpose |
|---|---|
Cause the current terminal line to send a CR as a CR followed by a NULL instead of a CR followed by a line feed (LF). |
This command ensures interoperability with different interpretations of end-of-line handling in the Telnet protocol specification.
Data transparency enables the Cisco IOS software to pass data on a terminal connection without the data being interpreted as a control character.
During terminal operations, some characters are reserved for special functions. For example, Ctrl-Shift-6-X (^^x) suspends a session. When transferring files over a terminal connection (using the Xmodem or Kermit protocols, for example), you must suspend the recognition of these special characters to allow a successful file transfer. This process is called data transparency.
You can set a line to act as a transparent pipe so that programs such as Kermit, Xmodem, or CrossTalk can download a file across a terminal line. To temporarily configure a line to act as a pipe for file transfers, use the following command in EXEC mode:
| Command | Purpose |
|---|---|
Set up the terminal line to act as a transparent pipe for file transfers. |
The terminal download command is equivalent to using all the following commands.
The classic U.S. ASCII character set is limited to 7 bits (128 characters), which adequately represents most displays in the U.S. Most defaults on the modem router work best on a 7-bit path. However, international character sets and special symbol display can require an 8-bit wide path and other handling.
You can use a 7-bit character set (such as ASCII), or you can enable a full 8-bit international character set (such as ISO 8859). This allows special graphical and international characters for use in banners and prompts, and adds special characters such as software flow control. Character settings can be configured globally, per line, or locally at the user level. Use the following criteria for determining which configuration mode to use when you set this international character display:
To specify a character set for all lines, use one or both of the following commands in global configuration mode:
| Command | Purpose |
|---|---|
Specify the character set used in EXEC and configuration command characters. | |
Specify the character set used in special characters such as software flow control, hold, escape, and disconnect characters. |
To specify a character set based on hardware, software, or on a per-line basis, use any of the following commands in line configuration mode:
| Command | Purpose |
|---|---|
databits {5 | 6 | 7 | 8} | Set the number of data bits per character that are generated and interpreted by hardware. |
data-character-bits {7 | 8} | Set the number of data bits per character that are generated and interpreted by software. |
exec-character-bits {7 | 8} | Specify the character set used in EXEC and configuration command characters on a per-line basis. |
special-character-bits {7 | 8} | Specify the character set used in special characters such as software flow control, hold, escape, and disconnect characters on per-line basis. |
To specify a character set based on hardware, software, or on a per-line basis for the current terminal session, use the following appropriate commands in EXEC mode:
| Step | Command | Purpose | ||
|---|---|---|---|---|
| Set the number of data bits per character that are generated and interpreted by hardware for the current session. | |||
| Set the number of data bits per character that are generated and interpreted by software for the current session. | |||
| Specify the character set used in EXEC and configuration command characters on a per-line basis for the current session. | |||
| Specify the character set used in special characters (such as software flow control, hold, escape, and disconnect characters) on per-line basis for the current session. |
Character padding adds a number of null bytes to the end of the string and can be used to make a string an expected length for conformity. You can change the character padding on a specific output character.
To set character padding, use the following command in line configuration mode:
| Command | Purpose |
|---|---|
padding ascii-number count | Set padding on a specific output character for the specified line. |
| Command | Purpose |
|---|---|
Set padding on a specific output character for the specified line for this session. |
You can specify the type of terminal connected to a line. This feature has two benefits: it provides a record of the type of terminal attached to a line, and it can be used in Telnet terminal negotiations to inform the remote host of the terminal type for display management.
To specify the terminal type, use the following command in line configuration mode:
| Command | Purpose |
|---|---|
terminal-type {terminal-name | terminal-type} | Specify the terminal type. |
This feature is used by TN3270 terminal to identify the keymap and ttycap passed by the Telnet protocol to the end host.
To specify the type of terminal connected to the current line for the current session, use the following command in EXEC mode:
| Command | Purpose |
|---|---|
terminal terminal-type terminal-type | Specify the terminal type for this session. |
Indicate the terminal type if it is different from the default of VT100. This default is used by TN3270 for display management and by Telnet and rlogin to inform the remote host of the terminal type.
To specify the current keyboard type for a session, use the following command in EXEC mode:
| Command | Purpose |
|---|---|
Specify the keyboard type for this session. |
You must specify the keyboard type when you use a keyboard other than the default of VT100. The system administrator can define other keyboard types and give you their names.
The screen values set can be learned by some host systems that use this type of information in terminal negotiation. To disable pausing between screens of output, set the screen length to a zero.
The screen length specified can be learned by remote hosts. For example, the rlogin protocol uses the screen length to set up terminal parameters on a remote UNIX host. The width specified also can be learned by remote hosts.
To set the terminal screen length and width, use the following commands in line configuration mode:
| Step | Command | Purpose | ||
|---|---|---|---|---|
| length screen-length | Set the screen length. | ||
| width characters | Set the screen width. |
To set the number of lines or character columns on the current terminal screen for the current session, use one of the following commands in EXEC mode:
| Command | Purpose |
|---|---|
Set the screen length for the current session. | |
Set the screen width for the current session. |
You can set up a line to inform a user who has multiple, concurrent Telnet connections when output is pending on a connection other than the active one. For example, you might want to know when another connection receives mail or a message.
To set pending output notification, use the following command in line configuration mode:
| Command | Purpose |
|---|---|
Set up a line to notify a user of pending output. |
To set pending output notification for the current session, use the following command in EXEC mode:
| Command | Purpose |
|---|---|
Set up a line to notify a user of pending output for the current session. |
The Cisco IOS software supports dispatch sequences and TCP state machines that transmit data packets only when they receive a defined character or sequence of characters. You can set up dispatch characters that allow packets to be buffered, then transmitted upon receipt of a character. You can set up a state machine that allows packets to be buffered, then transmitted upon receipt of a sequence of characters. This feature enables packet transmission when the user presses a function key, which is typically defined as a sequence of characters, such as "Esc I C."
TCP state machines can control TCP processes with a set of predefined character sequences. The current state of the device determines what happens next, given an expected character sequence. The state-machine commands configure the server to search for and recognize a particular sequence of characters, then cycle through a set of states. The user defines these states---up to eight states can be defined. (Think of each state as a task that the server performs based on the assigned configuration commands and the type of character sequences received.)
The Cisco IOS software supports user-specified state machines for determining whether data from an asynchronous port should be sent to the network. This functionality extends the concept of the dispatch character and allows the equivalent of multicharacter dispatch strings.
Up to eight states can be set up for the state machine. Data packets are buffered until the appropriate character or sequence triggers the transmission. Delay and timer metrics allow for more efficient use of system resources. Characters defined in the TCP state machine take precedence over those defined for a dispatch character.
Use the following commands in line configuration mode, as needed, for your particular system needs:
| Step | Command | Purpose | ||
|---|---|---|---|---|
| state-machine name state firstchar lastchar [nextstate | transmit] | Specify the transition criteria for the states in a TCP state machine. | ||
| dispatch-machine name | Specify the state machine for TCP packet dispatch. | ||
| dispatch-character ascii-number [ASCII-number2 . . . ascii-number] | Define a character that triggers packet transmission. | ||
| dispatch-timeout milliseconds | Set the dispatch timer. |
To change the packet dispatch character for the current session, use the following command in EXEC mode:
| Command | Purpose |
|---|---|
terminal dispatch-character ascii-number1 [ascii-number2 . . . ascii-number] | Define a character that triggers packet transmission for the current session. |
To display debug command output and system error messages in EXEC mode on the current terminal, use the following command in privileged EXEC mode:
| Command | Purpose |
|---|---|
Display debug command output and system error messages in EXEC mode on the current terminal. |
Remember that all terminal parameter-setting commands are set locally and do not remain in effect after a session is ended. You must use this command at the privileged-level EXEC prompt at each session to see the debugging messages.
To configure flow control between the router and attached device for this session, use one of the following commands in EXEC mode:
| Command | Purpose |
|---|---|
terminal flowcontrol {none | software [in | out] | hardware} | Set the terminal flow control for this session. |
Set the flow control start character in the current session. | |
Set the flow control stop character in the current session. |
| 1This command is seldom used. Typically, you only need to use the terminal flowcontrol command. |
For more information about setting flow control or to set flow control on a line for more than the current session, refer to the "Configuring Modem Support and Asynchronous Devices" chapter in the Dial Solutions Configuration Guide.
You can enable a terminal-locking mechanism that allows a terminal to be temporarily locked by using the following command in line configuration mode:
| Command | Purpose |
|---|---|
Enable a temporary terminal locking mechanism. |
After you configure the line as lockable, you must still issue the lock EXEC command to lock the keyboard.
You can configure a terminal to detect the baud rate being used over an asynchronous serial line automatically. To set up automatic baud detection, use the following command in line configuration mode:
| Command | Purpose |
|---|---|
Set the terminal to automatically detect the baud rate. |
To start communications using automatic baud detection, use multiple Returns at the terminal. A 600-, 1800-, or 19200- baud line requires three Returns to detect the baud rate. A line at any other baud rate requires only two Returns. If you use extra Returns after the baud rate is detected, the EXEC facility simply displays another system prompt.
You can set up a terminal line to appear as an insecure dial-up line. The information is used by the LAT software, which reports such dial-up connections to remote systems.
To set a line as insecure, use the following command in line configuration mode:
| Command | Purpose |
|---|---|
Set the line as a dial-up line. |
In the previous releases of Cisco IOS software, any line that used modem control was reported as dial-up connection through the LAT protocol; this feature allows more direct control of your line.
You can change these parameters as necessary to meet the requirements of the terminal or host to which you are attached. To do so, use one or more of the following commands in EXEC mode:
| Command | Purpose |
|---|---|
terminal speed bps | Set the line speed for the current session. Choose from line speed, transmit speed, or receive speed. |
You can record the location of a serial device. The text provided for the location appears in the output of the EXEC monitoring commands. To record the device location, use the following command in line configuration mode:
| Command | Purpose |
|---|---|
location text | Record the location of a serial device. |
If you attempt to connect to a remote device (such as a printer) that is busy, the connection attempt is placed in a terminal port queue. If the retry interval is set too high, and several routers or other devices are connected to the remote device, your connection attempt can have long delays. To change the retry interval for a terminal port queue, use the following command in global configuration mode:
| Command | Purpose |
|---|---|
terminal-queue entry-retry-interval interval | Change the retry interval for a terminal port queue. |
The Cisco IOS software supports a subset of the Berkeley UNIX Line Printer Daemon (LPD) protocol used to send print jobs between UNIX systems. This subset of the LPD protocol permits the following:
The Cisco implementation of LPD permits you to configure a printer to allow several types of data to be sent as print jobs (for example, PostScript or raw text).
To configure a printer for the LPD protocol, use the following command in global configuration mode:
| Command | Purpose |
|---|---|
printer printername {line number | rotary number} [newline-convert] | Configure printer and specify a TTY line (or lines) for the device. |
If you use the printer command, you also must modify the /etc/printcap file on the UNIX system to include the definition of the remote printer on the router. Use the optional newline-convert keyword on UNIX systems that do not handle single character line terminators to convert a new line to a character Return, line-feed sequence.
The following example includes the configuration of the printer Saturn on the host Memphis:
commlpt|Printer on cisco AccessServer:\ :rm=memphis:rp+saturn:\ :sd+/usr/spool/lpd/comm1pt:\ :lf=?var/log/lpd/commlpt:
The content of the actual file may differ, depending on the configuration of your UNIX system.
To print, users use the standard UNIX lpr command.
Support for the LPD protocol allows you to display a list of currently defined printers and current usage statistics for each printer. To do so, use the following command in EXEC mode:
| Command | Purpose |
|---|---|
show printer | List currently defined printers and their usage statistics. |
To provide access to LPD features, your system administrator must configure a printer and assign a TTY line (or lines) to the printer. The administrator must also modify /etc/printcap on your UNIX system to include the definition of the remote printer in the Cisco IOS software.
Posted: Wed Apr 28 10:10:02 PDT 1999
Copyright 1989-1999©Cisco Systems Inc.