What AT commands are required to register an IoT modem on Verizon

Question

I'm trying to troubleshoot a wireless modem that contains a Sierra MC73xx module. Also, my SIM is from an MVNO that says it has enabled roaming on Verizon.

I run AT+COPS=? and can see the Verizon network:

+COPS: (0,"T-Mobile","T-Mobile","310260",2),(0,"Verizon","Verizon","311480",7),(0,"T-Mobile","T-Mobile","310260",0),(0,"AT&T","AT&T","310410",7),(0,"AT&T","AT&T","310410",2),(0,"T-Mobile","T-Mobile","310260",7),,(0,1,2,3,4),(0,1,2)

However when I run AT+COPS=1,2,311480 I can't seem to register on the network.

Are there other AT commands required to register a roaming SIM on the Verizon network? BTW through testing, I've been able to register on T-Mobile and AT&T.

Answer 1

In the PLMN scan result, there is only one Verizon network, (0,"Verizon","Verizon","311480",7). "7" indicates the radio access technology(RAT) and I remember 7 is LTE.

On the other hand, both AT&T and T-Mobile has 2G/3G coverage, i.e. RAT 0 and 2. In your successful registration, you probably see the RAT is 0 or 2. You can use at!gstatus to check RAT.

I suspect your SIM card cannot roaming in Verizon LTE network. Usually international roaming agreement does not cover LTE.