We’re designing a pallet tracker for our own fleet: Quectel BG95-M3, GNSS, a 3.6 V Li-SOCl2 cell, wakes every 30 minutes and sends position and temperature to Hermetry over HTTPS. Module datasheet says GCF and PTCRB certified, so I assumed we’re fine on the cellular side.
Then a colleague from a previous job told me their trackers ran fine for two months and then got blocked by the operator one morning, “because the device wasn’t certified, only the module”. Now I’m second guessing. Do I need to certify the whole tracker? Is there some list the operator checks? We’re talking 300 units, not millions, and I don’t have budget for a full certification campaign.
The prototype on the bench registers fine with a normal IoT SIM:
AT+CEREG?
+CEREG: 0,5
AT+QCSQ
+QCSQ: "eMTC",-97,-128,48,-12We bought finished trackers, so no help sorry. Following though, we’re thinking about our own boards.
Module certification lowers what the end product has to repeat, it doesn’t replace it. Ask the operator’s IoT sales team what they require for a device on their network. Some just want the module’s approval and a registration of your device, some want lab testing on the finished product.
I’m not an engineer, but this happened to us last year, so here’s what I learned the expensive way.
We bought 12 leak sensors for our hotels from a small vendor, LTE-M, certified module, all reporting to Hermetry. Three months in, all 12 went offline on the same morning. I only noticed because the Device offline alarms fired for every one of them within ten minutes, before breakfast. The vendor spent a week on it. It turned out the operator had started rejecting devices whose IMEI range (the first 8 digits, the TAC) wasn’t registered with them as an approved device. The module had its approvals, but nobody had ever registered the finished sensor.
What fixed it: the vendor went through the operator’s device approval, which for a product built on a certified module was mostly paperwork plus a short field test. Our TAC got added and the sensors came back the next day with no changes on our side.
So for your 300 trackers, I’d call the operator now, before the build, ask what their approval looks like for a product on a certified module, and get your TAC registered. And set up a Device offline rule on the tracker profile. Your trackers wake every 30 minutes over HTTPS, so I’d set the profile to Recent message with something like 1,800 s times 2 and a short offline delay on top, so you hear about a block the same morning.
That’s the scenario I was scared of, thanks David. Called the operator: since our module is already approved, they want a form, the module certificate, and a two week pilot on their network. TAC registration is part of it. Pilot starts next month. Offline rule set to 3,600 s after the Recent message window, with 1,800 x 2 on the profile.
Good. Keep the operator’s approval email with the design file, the next hardware revision will need it again.
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