Hi Ades,OML is simply Operation and Maintenance Link thru which we at OMC can reach the BTS.Its a 16/64kpbs TS in the E1.When a BTS fails,(ie e1 is break) the OML also fails and we normally get an alarm ‘LAPD OML fault’.
LAPD is Link access protocol on the D link,a layer2 protocol,ensures error free Transmission.In the BTS normally TRX gets these alarms,straightaway check the e1 or for any loose connections in the BTS.if persists perform the ultimate mastersrtoke.
RESET. ;-D