Configuring Half-Duplex
Configuring Half-Duplex
Use the half-duplexcommand to configure PA-4T+ interfaces for half-duplex mode; full-duplex mode is the default for low-speed serial interfaces. Serial DCE interfaces in half-duplex mode can be configured for controlled-carrier mode or constant-carrier mode; constant-carrier mode is the default. Use the half-duplexcontrolled-carriercommand to configure a PA-4T+ interface for controlled-carrier mode. Use the no half-duplexcontrolled-carriercommand to return the interface to constant-carrier mode.
Controlled-carrier mode sets the PA-4T+ interface to deactivate data carrier detect (DCD) until a transmission is sent to the interface. After a transmission is received, DCD is activated and the interface waits a user-configured amount of time, then transmits the data. After the transmission, the interface waits a user-configured amount of time and then deactivates DCD.
Constant-carrier mode activates DCD at all times.
Follow these steps to configure controlled-carrier mode on a PA-4T+ interface:
Step 1 At the privileged-level prompt, enter configuration mode and specify that the console
terminal will be the source of the configuration subcommands, as follows:
Router# configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
Router(config)#
Step 2 Specify the interface to configure for controlled-carrier mode (using the subcommand interface, followed by the type [serial] and slot/port [port adapter slot number and interface number] and then the subcommand half-duplexcontrolled-carrier). The following example is for the first interface of the port adapter in slot 1:
Router(config)# interface serial 1/0
Router(config-if)#half-duplex controlled-carrier
Step 3 Specify the time that the interface delays when configured for controlled-carrier mode by entering the half-duplex timer {cts-delayvalue cts-drop-timeoutvalue dcd-drop-delayvalue dcd-txstart-delayvalue rts-drop-delayvalue rts-timeoutvalue transmit-delayvalue} command. The following example configures the DCD drop delay on the first interface of the port adapter in slot 1 for 100 milliseconds:
Router(config)# interface serial 1/0
Router(config-if)#half-duplex timer dcd-drop-delay 100 ms
Note Table 8-1 lists the default settings for each half-duplex timer.
Step 4 After including all of the configuration subcommands, to complete the configuration, enter Ctrl-Z(hold down the Control key while you press Z) or enter end to exit configuration mode and return to the EXEC command interpreter prompt.
Step 5 Write the new configuration to nonvolatile memory as follows:
Router# copy running-config startup-config
[OK]
Router#
This completes the procedure for configuring controlled-carrier mode on a PA-4T+ interface. For additional information on configuring half-duplex operation on low-speed serial interfaces, refer to the chapter “Configuring Interfaces” of the Configuration Fundamentals Configuration Guide publication. If you need more information, see the “Cisco Connection Online” section on page vii and the “Related Documentation” section on page vi.
