Andrew Corporation – Base Station Systems Group Page 4
Proprietary – Use pursuant to Company Instruction
Alarm System:
Alarms and operating state are communicated to the BTS via connections to the “Alarm
Terminal Block” at the back of the subrack. The terminal block is internally connected to
dry-contact relays which are located in the MCPA subracks.
ALARM
CATEGORY
SEVERITY
Minor
Conditions that do not immediately affect system operation, but lead to more serious problems if
ignored.
Major
Conditions that directly affect amplifier operation (e.g. reduced gain), but allow the system to
continue operating.
Critical
Conditions which result in sector shutdown, preventing any further cellular call traffic.
MCPA LEDs
MCPA LED
Status
Alarm Severity
Possible Failure Modes
Green: “ON”
Yellow: ON”
Red: “ON”
Initial Power-up of
MCPAs.
NONE
LEDs all “ON” simultaneously for about 2 seconds.
Green: “ON”
Normal Operation
NONE
Green: “ON”
Yellow: ON”
Minor
1. MCPA Fan(s) failure
2. MCPA high internal temperature (approximately between 80°C
and 90°C).
3. MCPA values indicating: Poor Return Loss (3-8 dB)
Yellow: ON”
Major
1. RF disabled via MCPA panel switch or RFIM command
2. RF Overdrive (gain reduced)
3. DC voltage out of normal range
Red: “ON”
Critical
1. MCPA internal failure
2. RF Overdrive (> 10 dB)
3. MCPA high internal temperature
(above approximately 90°C).
4. MCPA values indicating: Poor Return Loss (0-3 dB)
