61202129L1-1 TSU 120 User Manual D-1Appendix D System MessagesThis appendix lists and defines the alarm and status messagesthat appear on the TSU 120 screen.ALARM MESSAGESNetwork Interface (NI)Nx56/64 InterfaceThe following messages indicate an alarm condition on theNx56/64 card:Red Alarm NI unable to frame align with incoming signalYellow Alarm Remote alarm indication (RAI) being receivedfrom far endBlue Alarm Unframed all ones (1s) (AIS) being received at NILoss of Signal No signal detected at NIClock Slip Difference in frequency of the data clock at thenetwork and DTEPLL Alarm Unable to achieve Phase-locked Loop on theclock provided by the network interface.Zeros Alarm All zeros (0s) data being sent toward the networkinterfaceNo EXT Clock No external transmit clock at DTE (only appearsif EXT CLK is selected)
