Modem Signal and Line States
Signal and Line State Diagrams
Configuring a Line to Disconnect Automatically
To configure automatic line disconnect, use the following command in line configuration mode:
Command | Purpose |
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Configures automatic line disconnect. | |
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The autohangup command causes the EXEC facility to issue the exit command when the last connection closes. This feature is useful for
Supporting Reverse Modem Connections and Preventing Incoming Calls
In addition to initiating connections, the Cisco IOS software can receive incoming connections. This capability allows you to attach serial and parallel printers, modems, and other shared peripherals to the router or access server and drive them remotely from other
The specific TCP port or socket to which you attach the device determines the type of service that the Cisco IOS software provides on a line. When you attach the serial lines of a computer system or a data terminal switch to the serial lines of the access server, the access server can act as a network
The Cisco IOS software supports ports connected to computers that are connected to modems. To configure the Cisco IOS software to function somewhat like a modem, use the following command in line configuration mode. This command also prevents incoming calls.
Command | Purpose |
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Configures a line for reverse connections and prevents incoming | |
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Figure 29 illustrates the modem callout process. When the Cisco IOS software receives an incoming connection, it raises the DTR signal and waits to see if the CTS signal is raised to indicate that the host has noticed the router DTR signal. If the host does not respond within the interval set by the modem answer-timeout line configuration command, the software lowers the DTR signal and drops the connection.
Cisco IOS Dial Technologies Configuration Guide
