Check the transmission links by looping back the RX0 and TX0 ports of the BTS3001.
If the sub-category No. is 0 and the BTS3001C works in the E1 transmission mode, set the RX0 and TX0 ports of the BTS3001C to a local loop. If the sub-category No. is 0 and the BTS3001C works in the optical transmission mode, set the westward optical ports of the BTS3001C to a local loop. After that, check whether the LIU indicator in the maintenance cavity is off.
If the sub-category No. is 1 and the BTS3001C works in the E1 cascading mode, set the RX1 and TX1 ports of the BTS3001C to a local loop. If the sub-category No. is 1 and the BTS3001C works in the optical transmission cascading mode, set the eastward optical ports of the BTS3001C to a local loop. After that, check whether the alarm is cleared.
Y=>The LIU indicator is off or the alarm is cleared, the transmission link of this BTS3001C is normal. is normal.
N=>The LIU indicator is on or the alarm is not cleared, the transmission link of this BTS3001C is abnormal.