Sending Data over Cellular Networks

[chipfryer27]

Hi

I notice some differences I'm putting down to AT / firmware versions.

Issuing the same code to each module

AT+HTTPPARA="URL","http://aaa.bbb.ccc.ddd/update.php?Sensor=x&Value=y" // where x and y are variables

7670 doesn't care if the http:// etc is within quotation marks or not. 7600 insists that it is. Both can update my RAMP install.

Modifying the above line for ThingSpeak, the 7670 can update, the 7600 has a 406 error returned.

Fun, fun, fun.....

Regards

[chipfryer27]

Hi

Frustrating..... Whilst I can get details of the modules using AT+SIMCOMATI it doesn't appear to return AT version so I'm still no further forward in establishing which versions are installed, other by trial and error.

Try a command and if it is accepted, good, if not trawl backwards until you find the version that differs, try that, repeat....... To add pain to misery even minimum timeout values have changed. Previously you may have had abc,0,20 now you need abc,0,60 (or whatever) if using an older version.

On the bright side, I wrote a brief chart to make a call and then hang up (no point in trying to reuse any SIM800 code as pretty much all has changed) and as I'm using the UART component, I can simulate, select my com port, and have the chart talk to the SIM7670 module via the USB-TTL adapter (FT232 of course). I've only used the Flowchart to make / end a call to my phone over the cellular network, nothing else yet, but as Flowcode allows me to simulate with the SIM7670 / 7600 hardware it makes things a lot easier.

I thought I'd managed to get the 7600 updating ThingSpeak. ThingSpeak informed that the chart had been updated "less than a minute ago" but no values were actually displayed. Soon thereafter I couldn't get the 7600 to do anything so had to issue AT+CFUN=1,1

Regards

[chipfryer27]

Hi

It would appear that my 7600 uses AT v2.xx whilst my 7670 uses AT v3.0 and as such there are obviously differences in not just commands but structure too. Do note that I still haven't found a way to establish exactly what is installed, I'm guessing based on what commands are accepted or rejected.

I managed to get both modules to send and receive SMS messages, and via MQTT update Thingspeak and my own mosquitto broker. However using HTTP, whilst both can also update my RAMP install, only the 7670 could update ThingSpeak. Using the 7600 the server always returned an error code and I long suspected something within the Headers was troublesome.

With a bit of time today (can't move coz still digesting chocolate eggs) I had Firefox then modules update my RAMP. I then looked at the apache logs and saw that first off, the 7600 is HTTP/1.0 whilst the rest are HTTP/1.1 which lead me to dig deeper.

Rabbit hole after rabbit hole was entered (well it is Easter....) and eventually I discovered that as suspected I need to set/modify Headers when using the 7600 (running AT v2.xx?). With the changes incorporated into my Terminal Macros I can now use the 7600 to update ThingSpeak using HTTP.

So, now that I have both modules doing everything that I'd want them to do I'll write up the AT Commands I used. Once done I'll post then create some basic Flowcode charts.

Regards

[chipfryer27]

Hi

I was following SIMCOM's documentation which for the 7670 module showed as 76xx on their website. The AT commands for such go up to, as far as I'm aware, v3.0 which was released 2021. I have now just found a document from another source that is marked SIM767x v1.01 released 2023. This could be more applicable. So far I haven't found any difference between 76xx v3 and 767x v1.01 and I would expect any to be minor, as the 7670 seems to accept all v3.0 commands I have issued so far.

Again, a lot of confusion out there for these and similar modules.......

Regards

[chipfryer27]

Hi

Attached is a guide to using the 7670 and 7600 modules.

In it I document the AT commands I issued using a terminal program to instruct and interrogate the modules. Note that this is how I did it and it is not the only way to do things, and is only a guide, not a training course

The version of AT commands installed in your module will determine whether or not the commands I document work or not.

Using the guide, from my terminal program I could send and receive SMS messages, update sites such as ThingSpeak, and publish and subscribe to MQTT brokers. As mentioned in previous posts, I created a RAMP server which I used for testing and some of my commands reference scripts applicable to such. However you can easily modify to suit.

Using Flowcode and the UART component it should be easy enough to create your own Flowcharts to interact. When I have time I will create some simple charts based on the guide and post.

Hopefully this will be of some help.

Updating Services over Cellular Networks.pdf

(127.75 KiB) Downloaded 4 times

Regards