Line Fail
  
  Sent when the UPD goes on-battery, repeated every 30 seconds until low-battery condition reached. Sometimes occurs more than once in the first 30 seconds.
Return from Line Fail
  
  UPS back on line power, only sent if a Line Fail has been sent.
  
Low Battery
  
  Sent to indicate low battery, but not on SmartUPS v/s or BackUPS Pro models.
  
Return from Low Battery
  
  Sent when the battery has been recharged to some level, only if a Low Battery has been sent previously.
  
Abnormal Condition
  
  Sent for conditions such as “shutdown due to overload” or “shutdown due to low battery capacity”. Also occurs within 10 minutes of Turn On.
  
Return from Abnormal
  
  Sent when the UPS returns from an abnormal condition where Abnormal Condition was sent, but not a Turn On. Not implemented on SmartUPS v/s or BackUPS Pro models.
  
About to Turn Off
  
  Sent when the UPS is about to switch off the load. No commands are processed after this character is sent. Not implemented on SmartUPS v/s, BackUPS Pro, or third generation SmartUPS models.
  
Replace Battery
  
  Sent when the UPS detects that the battery needs to be replaced. Sent every five hours until a new battery test is run or the UPS is shut off. Not implemented on SmartUPS v/s or BackUPS Pro models.
  
Check Alarm Register for Fault (Measure-UPS)
  
  Sent to signal that temperature or humidity is out of set limits. Also sent when one of the contact closures changes states. Sent every two minutes, stops when the alarm conditions are reset. Only sent for alarms enabled with I. Cause of alarm may be determined by asking the UPS. Not implemented on SmartUPS v/s or BackUPS Pro.
  
Variable Change
  
  Sent whenever any EEPROM variable is changed. Only supported in EEPROM on Matrix UPS and third generation SmartUPS models.