What is the cheapest LTE-M suppoprting module?

Meanwhile I am inclined to not use this BC660K modules in the current project. The reason is: This module is a nightmare when used in a mobile environment (but works fine in stationary operation).

So I am looking for a replacement which …

  1. … should be as pin-compatible as possible to BC660K, most connections along borders.
  2. … must allow NB-IoT and also LTE-M. Absolutely mandatory is cell-roaming (transparent changeover between radio-cells). Must support EMEA area (at least Austria + Germany) or more.
  3. … is command compatible to BC660K. If so, I could use the same software with BC660K and this replacement one.
  4. … must have a good (low) price.

Which modules are matching my needs? Can somebody please help?

You can choose EG800Q

Isn’t that LTE Cat 1 only?

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I decided to build the new board with BG950A-GL module.
That module supports: CAT-M1 and NB1 (why doesn’t is also support NB2, I don’t know).
And it has built in GNSS. So I save cost and space for a separate GPS module.

rastik, I have a question to you (herbert.pan-Q appears to have problems understanding the difference between BINARY and ASCII transmission):

  • Can BG950A send BINARY data? I am pretty sure that BC660K can not, but BG950A is a lots more powerful, so it possibly can? It would halve the data volume when I do not have to send all data in HEX-ASCII.

About built-in GNSS receiver of BG950A-GL:
BG950A has a built-in GNSS receiver. The datasheet (Hardware Design) mentions that NMEA DATA are sent out on CLI_TxD1, Pin 27, and there is also CLI_RxD1, Pin 28…

  • Does BG950A automatically start sending NMEA sentences when it receives GPS signals, or not? If all GPS commands can be sent from MAIN_UART, I don’t really need CLI_RxD1, no?

  • I need the $GPRMC sentences in 9600/N/8/1, because there I find all required data. Sentences are like this one below:
    Finding all the .pdf reference files is literally an odyssee for BG950A-GL. I was able to find an “AT Command Reference”. but this one only forwards me to Document 8 for GPS related commands.

Where can I download all documentation for BG950A-GL ?
I need following documentation:

  • Complete set of AT-Commands for configuration, using TCP/IP (IPv4), using GPS, …
  • Can one provide a good initialization sequence for Internet-communication in Austria and Germany?
  • Does BG950A-GL support CELL roaming (forwarding from one radio cell to another)? I have SIM open for any network, and also allowing LTE-M and NB IoT, and GPRS from T-MOBILE. This ones I have to use.
  • Does BG950A-GL register lots faster in LTE-M (and/or NB IoT) compared to BC660K? I am watching the BC660K for hours until is gets registered. This is ways too slow, not to say useless. This may be useful for reporting usage of toilet paper, but not for data communication. I need to send 1800 Byte of data every 10 minutes.

Both modules can send binary data, we use them this way. While with BC660K you use AT+QISEND, with BC950A you need to use AT+QISENDEX.

Hi, rastik.

Thanks for this info.

Do you also have experience with GNSS in BG950A-GL modem? See my former questions. I corrently cannot test because I didn’t build up a modem yet (no PCB and no module arrived yet)

LTE-M network search is A LOT faster than NB-IoT. If you try to use BG950A in NB-IoT-only mode or when there’s no LTE-M network available, you’ll see similar search times. With NB-IoT it’s important to limit the band that are searched, default config with result in very long times. Look for AT+QBAND command and BC660K-GL Network Searching Scheme Introduction document. BG950A has similar command AT+QCFG="band".

There’s a whole set of documents for BG950A (they share a lot with other BG95x and BG77a), ask Quectel if you don’t have access to them.

NMEA sentences are directly accessible via USB, DEBUG or AUX port, depending on the configuration. You should be able to get them to MAIN UART via EMUX feature, but that’s more complicated.
If you only need RMC sentences, you can query them via AT+QGPSGNMEA="RMC", just repeat command as needed.

But remember that GNSS cannot be used simultaneously with network connection and that the power consumption is much higher to what you’d get when using separate GNSS receiver. BG951A works better here, even though the consumption is still not the best you can get.

Hi, again.
Thanks for this valuable information.
I am pretty sure you know this little GPS receivers based on UBLOCKS 6 or higher, like GY-GPSV3-NEO M8N. It works so well. I have to setup absolutely nothing, it does what I need out of the box. And it is so sensitive that it offers time and date a few seconds after power up - even when not sufficient satellites are found yet (so it supplies NMEA sentences with some empty fields.
That one I currently use. Works like a charm, so I will continue using it.

Power consumption is not really of importance in my case, but the documentation of BG950A is so thin that I have no good feeling Instead, I really feel that I will have sufficient troubles even without using GNSS until I get the BG950A fully under control.

You can get very good GNSS receivers from Quectel as well. Those on Airoha chipsets introduced last year work very well. Or use BG951A that has a separate received included in the module.