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This topic describes the unified gateway physical connection with the E1/T1 trunk cable and common E1/T1 alarms.
Physical Connection
The E1 and T1 trunks use the same physical cable. The following uses the E1 trunk as an example.
The unified gateway is connected to the peer device with the E1 cable.
E1/T1 Alarms
E1/T1 alarm types include:
ϒ⁄Fault alarms
A fault alarm is generated when the device is faulty. You must rectify the fault so that the system can be restored. Common fault alarms include:
§Loss of signal (LOS)
When a device cannot detect a signal, an LOS alarm is generated. When the device detects the signal, the LOS alarm is cleared.
§Loss of frame alignment (LFA)
An LFA alarm and an LOS alarm occur simultaneously. The LFA alarm is cleared after frame alignment.
§Alarm indication signal (AIS)
The peer device cannot correctly receive frame alignment signals.
§Remote alarm indication (RAI)
An RAI alarm indicates that the peer device cannot detect any signals. This may occur because the UScale X1960 fails to send signals, the UScale X1960 is disconnected, or the peer device fails to receive signals.
ϒ⁄Event alarms
Event alarms do not normally require any handling.
The algorithms used to detect the CRC bit in sub-multiframes are different for E1 and T1: E1 uses CRC4 while T1 uses CRC6.
E1-specific Alarms
ϒ⁄Loss of multiframe alignment (LMFA)
When two consecutive error multiframe alignment signals are received, the LMFA alarm is reported.
ϒ⁄Remote multiframe alignment (RMFA)
When a PCM terminal detects multiframe loss or TS16 alarm indication signal (AIS) alarm, the PCM terminal sends an RMFA signal to the peer device, indicating a reception fault.
ϒ⁄TS16-AIS
A device sends all 1 signals in 16 timeslots to indicate that a critical fault occurs and the device is unavailable.
Parent Topic: Background