LTE-M module not registering on network — AT+CEREG? keeps returning 0,2 in Australia

Seen this pattern a few times deploying on Australian carriers. Work through these in order — most LTE-M registration failures come down to one of four causes, and they're easy to distinguish with the right AT commands.

1. Check whether the radio is actually on

+CEREG: 0,0 (not registered, not searching) often means the module's radio is disabled, not that registration failed. Check functionality mode first:

AT+CFUN?

If it returns +CFUN: 0 (minimum functionality) the modem stack is running but the radio is off — the module won't search at all. Some SIM7080G firmware versions default to CFUN=0 after a fresh boot. Set it to full functionality:

AT+CFUN=1

If +CFUN: 1 is already the response, this isn't the cause.

2. Lock to Australian LTE-M bands

This is the most common cause of CEREG: 0,2 that never resolves, especially when AT+COPS=? comes back empty. If the module is searching across its global band mask, it may be spending most of its scan time on bands that no Australian carrier deploys for LTE-M.

On the SIM7080G, check what bands are currently configured:

AT+CBANDCFG?

For Telstra LTE-M in Australia, you want Band 28 (700 MHz APT) as the primary band. Telstra also uses Band 3 (1800 MHz) for LTE-M in metropolitan areas, typically alongside Band 28 for wider coverage. Lock to both:

AT+CBANDCFG="LTE-M",28,3

After changing the band config, restart the module with:

AT+CFUN=1,1

This resets to full functionality and forces a fresh network scan. In my experience, if band lock was the issue, you'll have CEREG: 0,1 within about 60 seconds of the module coming back up.

Note that band commands are module-family specific — the SIM7080G syntax above differs from Quectel BG95 or u-blox SARA-R4 equivalents, so check your AT command manual if you're on a different module.

3. Confirm the SIM is readable by the module

Even if AT commands work, a SIM seating issue can prevent registration:

AT+CCID

This returns the ICCID (the 20-digit number printed on the SIM). If you get ERROR, the SIM isn't being read — check the physical socket and try reseating it. Then:

AT+CIMI

This returns the IMSI, which the carrier uses to identify the subscriber. You need both CCID and CIMI to return valid values before registration is possible.

4. SIM provisioning for LTE-M

This is the one that isn't obvious from the AT command side. A SIM can return CCID and IMSI correctly and still fail LTE-M registration if the carrier hasn't enabled the right service profile on the account.

Not all Telstra SIMs support LTE-M out of the box — it depends on the specific plan and whether LTE-M capability has been activated on the subscriber account. If the SIM profile doesn't include LTE-M access, the network denies registration. From the module's perspective this looks almost identical to CEREG: 0,2 (searching) — the difference is that the module never transitions to 0,3 (registration denied) because the denial can be silent at the search layer.

Confirm with Telstra IoT support that LTE-M is actually activated on your SIM. If you ordered a "Basic IoT" SIM, it may require an activation step or a specific add-on before LTE-M registration is permitted.

Start with CFUN and band lock — they're the quickest to check and cover the majority of cases. Post what AT+CFUN? and AT+CBANDCFG? return and we can narrow it down.