Wp7610/wp7611 volte

IoT Modules WP Series
1

Hi All. I’m trying to make VOLTE calls on my device using AT commands, and I only get errors. We have devices in the field that stopped making calls when ATT shut down 3G. I can make calls with my device in Canada if KSRAT = 0. If I force it to LTE only KSRAT=5, I get errors. Any ideas how to make voice calls work for LTE.

SWI9X07Y_02.37.03.00 73df45 jenkins 2020/04/08 10:59:14
!GETRAT: LTE
Index, Name, GW Band Mask L Band Mask 1 TDS Band Mask L Band Mask 2f
00, All bands, 0000000006800000 000000000300381A 0000000000000000 0000000000000042
!GETBAND: LTE B2
!SELRAT: 06, LTE Only
LTE Rx chan: 1075
LTE Tx chan: 19075
LTE CA state: INACTIVE
EMM state: Registered Normal Service
RRC state: RRC Connected
PCC RxM RSSI: -83
RSRP (dBm):-106
PCC RxD RSSI: -95.
RSRP (dBm): -135
Tx Power: –
TAC: 5A05 (23045)
RSRQ (dB): -7
Cell ID: 010B6117 (17522967)
SINR (dB): 19.6
IMS reg state: UNKNOWN
IMS mode: Not Support
IMS Srv State: UNKNOWN SMS,UNKNOWN VoIP
LTE band: B2
LTE bw: 15 MHz
+CSQ: 17,99
+CME ERROR: no network service

2

Hi kimk,

As your log file provided, the IMS Srv State: UNKNOWN SMS,UNKNOWN VoIP means your module does not have the VoLTE call feature.
Please try configuring CID=2 with IMS APN for VoLTE certified with AT&T carrier that UE will connect to IMS client. Then use AT!GSTATUS? command to check IMS Srv State.

3

Update I was finally able to make a VoLTE call by cheating and sticking my SIM in an iphone first. That tricked the network into providing the IMS service.
It persisted for about 10 mins until the network realised it wasn’t an iphone and IMS went back to no service. It seems telecoms are determining IMS service based on IMEI allocations.