Does anyone have any experienced knowledge about available GSM modules which support 4g and/or 5g? I've started a project with a SIM808, only to have my hopes dashed by the news that 2g networks won't be in operation much longer.
I’ve been using both for about 4 years (around 100 units total)
The SIM 5320 (3G), and SIM 7600 (4G) have been bulletproof.
Check the version is suitable for the carriers and bands where they’re going to be deployed.
I’m curious about this area of >2G as well and I’m pleased to hear of some positive experience with specific modules. We’re losing 2G here as well.
@lastchancename I've recently started playing around with the SIM7600CE-T. I'd started developing my own AT/URC command parser... is there anything out there that you would recommend? ... rather than me reinventing the wheel. Initially just interfacing with an Uno... although will possibly move to something with more hardware serial ports.
Yeah more hardware serial is a good thing…
For a parser, they’re all a bit specific, so I end up writing my own. It’s not too hard if you’re patient.
The trick with the modem, is that some operations take from milliseconds to seconds to complete, and you don’t want to block your processor for that long.
The most difficult thing I found is handling unexpected ‘service messages’ sent by the carrier, or wrong numbers.
My modem handlers (originally based on FONA), are heavily modified, and use a state machine to interact with the various phases of some activities - no blocking.
It was a bit of work, but was well worth the effort.
I was hoping to rewrite it as a class/library but health issues got in the way.
Yes, that's the same conclusion I've come to... it's not too bad interpreting responses to commands sent... but when they get interrupted with incoming calls or SMS messages then it can get messy very quickly.
And as you mention there are quite big timing difference so you can have sent a 2nd message before you get a response to the first, etc.
It also seems that there aren't consistent start and end character sequences, so it can be a bit tricky to figure out where messages start end end. In my case I'm only using a fairly small set so will just work through them one at a time.
You do have another option…
I personally avoid the message storage in the. modem, and handle each notification as it arrived, but to accommodate frequent messages, there may be some benefit in using the on-chip storage - but then you have to manage, read and delete the stuff in those memories.
I don't wish to hijack the thread but this is not completely irrelevant. Has anyone any practical experience of using a normal smartphone over Bluetooth to access mobile network service from an MCU but with a reasonable power usage profile possibly involving powering up the phone, without manual intervention from the user, for a short session, then powering it down again. Clearly with a 4g/5g type module the user has full control over the device for the purposes of minimising power consumption.
What modules have you been using specifically?
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