Answer: NMO means Network Mode of Operation.
NMO1: which means there’s a Gb interface between MSC and SGSN, Then UE will make a separate attach procedures for CS and PS in a sequence.
NMO2: Which means there’s no Gb interface between MSC and SGSN. Then UE can make the combined registration procedure for CS and PS service.
Telenor SE - new network code is 24024 in NMO1.
Telenor SE - old network code is 24008 in NMO2.
In spytrace log, we can see RR sends MMM the message of “RR_ACT_IND”:
If the field v_NetworkMode = 1, it means NMO2, separate register procedures for CS and PS
If the field v_NetworkMode = 0, it means NMO1, combined register procedures for CS and PS