194 CHAPTER 11: F UNDAMENTAL SERIAL I NTERFACE CONFIGURATION COMMANDSParameter dsr-dtr: Detects DSR (data set ready) and DTR (data terminal ready) signals ofDSU/CSU (data service unit/channel service unit).dcd: Detects the DCD (data carrier detect) signal of the DSU/CSU on the serialinterface.Description Use the detect command to enable data carrier detection as well as leveldetection on the serial interface.Use the undo detect command to disable data carrier detection as well as leveldetection on the serial interface.By default, data carrier and level detection is enabled on serial interfaces.If level detection is disabled on an asynchronous serial interface, the systemautomatically reports that the state of the serial interface is up with both DTR andDSR being up without detecting whether a cable is connected. If level detection isenabled on the interface, the system detects the DSR signal in addition to theexternal cable. The interface is regarded up only when the detected DSR signal isvalid. Otherwise, it is regarded down.When determining whether a synchronous serial interface is up or down, thesystem by default detects the DSR signal, DCD signal, and presence of cableconnection. Only when the three signals are all valid will the interface be regardedup. If level detection is disabled, the system considers that the interface is up withboth DTR and DSR being up after detecting the cable connection.n The modem command and the undo detect dsr-dtr command are mutuallyexclusive.Example # Enable data carrier detection on synchronous serial interface 2/0. system-view[Sysname] interface serial 2/0[Sysname-Serial1/0] detect dcdeliminate-pulseSyntax eliminate-pulseundo eliminate-pulseView Asynchronous serial interface viewParameter NoneDescription Use the eliminate-pulse command to eliminate the pulses with a width less than3.472 us, thus increasing signal reliability. This is useful when the line is seriouslyinterfered.
