Chapter 4. Status4-10 MX2800 STS-1 User Manual 61200659L1-1• LOS/AIS – indicates that the clock source is not valid due to anLOS or AIS condition.• F AIL – indicates that an internal hardware failure on the unitprevents the clock source from being used.• U NAVAILABLE – indicates that the user has specified a T1/E1port to be used as an external clock source, but the port has notbeen enabled.VT/PORT STATEThis field displays the current alarm condition of the VTs/ports.Possible conditions are given in the following chart:VT/Port StateAlarm DescriptionOFF VT in unequipped and T1/E1 port is disabled.OK VT/Port is in a normal state.LOS (T1/E1 Loss of Signal)The unit has lost the receive signal on a T1/E1.CAIS (Carrier Side AIS)The T1 is receiving all ones from the STS sideof the network.LAIS (Loop Side AIS)The T1 is receiving all ones from the DSX-1interface.XCV (T1/E1 Excessive Code Violations)The controller card is receiving excessive codeviolations, exceeding the threshold set by theuser (see XCV Threshold on page 3-12).
