• After the integration is completed, you might have some alarms that must be addressed on site. Usually, these alarms are hardware related. Below are examples and some suggested steps on how to clear them:

NOTE: A more detailed explanation on the kind of alarms, the possible causes and the specific instructions on how to address them can be found in ALEX documentation. The steps on how to open ALEX is mentioned under the section HOW TO VERIFY DUL/DUS ALARMS USING ALEX.

• RI Link failure alarm (electrical or optical) – This alarm could be the result of a faulty port on a DU, faulty port on radio, bad SFP, or faulty CPRI cable itself.

To resolve the alarm, do the following:

• Check CPRI cable terminations

• Swap CPRI cables

• Check or replace SFP module

• Replace CPRI cables with a known good one

• If it is a New Site Build, it could be that the fiber jumper used was not the one specified by T-Mobile. Installers sometimes use a type of fiber jumper in which the TX and RX lines on the LC connector are switched. In this case, the TX and RX fibers need to be switched in order to establish link between the DU and radios.

• Replace any faulty or defective component.