I have hologram.io Zone 2 sim cards and I can see Tmobile showing NBIOT coverage with the AT+COPS=? command on my BG96 modem in Northern Washington State but I cannot register for some reason. Should this work???
I don’t know if it the same with Hologram, T-Mobile’s NB-IOT network, and your BG96 modem, but when we were working with a MultiTech MTSMC-MAT1 (4GLTE Cat.M1) modem and the AT&T Cat M1 network with a Hologram SIM, anytime we changed APNs with the AT+GCDCONT=1,“IP”,“apn.konekt.io” command, we found that we also needed to execute an AT+COPS=2,0 to de-register from the network, then execute an AT+COPS=0,0 to re-register again before the modem actually showed that it was registered roaming on the AT&T network with an AT+CREG? (or AT+CGREG? or AT+CEREG?) command, and that it was using Cat M1 as the Access Technology with an AT+COPS? command .
After changing the APN with the AT+GCDCONT command, we also found we could power cycle or reset the modem, instead of executing the AT+COPS=x,0 commands, and it would also register correctly, too.
Please let me know if your modem works this way with the T-Mobile NB-IOT network.