98-16081aDataPortLEDsNETDSU/CSU3166Port1OKFailTestSigOOFAlrmEERDTRTXDRXDCTSRTSSelectInOutNetMonSDCP Operation3-6 3166-A2-GB20-20March 1999Table 3-3. Data Port (Port1) LEDsName Color MeaningDTR Green Monitors the state of interchange circuit CD (CCITT 108/1, /2) –Data Terminal Ready received from the synchronous data DTE.ON : DTR is being asserted by the synchronous data DTE.OFF : DTR is not being asserted.TXD Green Monitors activity on interchange circuit BA (CCITT 103) –Transmitted Data. This is the data sent from the synchronousdata DTE to the data port on the DSU/CSU.ON : Ones are being received from the synchronous dataDTE.OFF : Zeros are being received from the synchronous dataDTE.CYCLING: Both ones and zeros are being received from thesynchronous data DTE.RXD Green Monitors activity on interchange circuit BB (CCITT 104) –Received Data. This is data sent to the synchronous data DTEfrom the data port on the DSU/CSU.ON : Ones are being sent to the synchronous data DTE.OFF : Zeros are being sent to the synchronous data DTE.CYCLING: Both ones and zeros are being sent to thesynchronous data DTE.CTS Green Monitors the state of interchange circuit CB (CCITT 106) –Clear-to-Send sent to the synchronous data DTE.ON : CTS is being asserted by the DSU/CSU.OFF : CTS is not being asserted.RTS Green Monitors the state of interchange circuit CA (CCITT 105) –Request-to-Send received from the synchronous data DTE.ON : RTS is being asserted by the synchronous data DTE.OFF : RTS is not being asserted.
