BC95-G - PPP connection over Nb-IoT possible?

IoT Modules
1

Title says it all - I’m trying to get a PPP connection (using Linux, currently, but having plans to switch over to embedded if it works) using a BC95-G and a SIM of german provider 1nce.
So far I had no luck in establishing a connection via PPP (using pppd) - regular setup via AT commands goes well, module is registered to the network, also PDP context definition works, but when trying to dial ATD*99# or any thinkable variation thereof, I’m just getting an error.

Shouldn’t be Nb-IoT similar enough to other 4G technologies for this to work? Am I missing something, or is the module not capable of doing this?

Thank you for pointers in any direction!

2

hi,fgdotde:
Nb-iot is different from LTE(4G). Nb-iot mainly uses narrow band for simple or small amount of data transmission. It does not support SMS and dial-up, so ATD errors occur. Common usage scenarios/application protocols such as TCP/UDP, MQTT, CoAP, LwM2M, etc.
If you need to know more, you are advised to download the corresponding technical manual or materials from our official website.

3

Thank you for your quick answer! I should have mentioned that I’m aware of the restrictions that Nb-iot as a radio technology comes with (at least mostly, I’d say). However, your answer makes perfect sense w/ regard to the modem and the ATD command in a way as well - why have dialing if theres no numbers to dial.

Thus, I think I’d need to rephrase my question quite a bit - as we do have the part of LTE in Nb-Iot which enables IP communication to (except with NIDD), which is also visible by using AT commands and getting the module’s IP, and we are also able to do TCP and UDP on top (although I’m aware it is not recommended or very efficient with Nb-Iot), would it be possible to access these features with anything else but AT commands?
There’s for example other modems which only use PPP to communicate with the embedded device, but are using other protocols for the radio link.

Some background to clear things up a bit, maybe: I’m working on a legacy solution running on 2G (GPRS), which should be well within the limits of Nb-Iot when it comes to latency and data amount. However, until now, a quite “classic” PPP stack with TCP/IP/MQTT is used. There’s plans for a transition to CoAP or LWM2M over Nb-Iot with the next future major release, but until this is done, we’d like to upgrade to the most energy-conserving, IP-capable radio technology that can still be used with the PPP stack, but is also capable of CoAP/LWM2M later.
If I understand you correctly, this might only be either Nb-Iot with a modem that acts as a PPP peer to our embedded device, or a different radio access technology (I guess LTE-M would be the next one to consider).

4

hi,fgdotde:
If the NB-iot network is deployed locally, you can use BC95G;Generally, NB applies to medium and low rate transmission scenarios, CAT1 applies to medium rate transmission scenarios, but LTE applies to high rate transmission scenarios.Currently, BC95G supports TCP, UDP, MQTT, CoAP, and LwM2M.

5

Just to let you know that It’s possible to use PPP connection with Cat-M1 at least. I’ll test it with NB-IoT soon, anyway, I think that it should work as well. You can see if your modem has PPP protocol support to ensure that it’ll work within the modem specifications. In my case, I used BG770A-GL, which supports PPP, and NuttX RTOS, which has natively the PPPD app, which helped me a lot to get connected using that approach.

I only had to define my PDP context, use AT+COPS to get registered and connected, and use ATD*99# to start the dial-up on the modem.

To define the PDP context (replace the variables according to your internet provider):
AT+CGDCONT=1,“IP”,“virtueyes.com.br”
AT+CGAUTH=1,1,“virtu”,“virtu”

To get registered manually:
AT+COPS=1,2,“72410”,7

A hint to see your internet provider ID is using the AT+COPS=?, since it will show all the networks your module sees.

If you are not seeing anything, you can set the band used in your country, for instance, in Brazil we use Band 3 (0x4) for CATM1 and Band 28 (0x8000000) for NB-IOT, so you need to find the correspondent hex numbers in the datasheet to use in the following command:
AT+QCFG=“band”,0x0,0x4,0x8000000

Finally, the dial-up command:
ATD*99#

Like you, I was wondering if it would be possible, so I’ve just done a PoC to confirm that it’s definitely possible. Of course, it’s not the best approach with this kind of modem, but, it works.