About GSM module


I want to ask if i can replace my SIM800C module with the 4G module SIM7600. If yes where can i found the module ?

Is it possible or I must replace all the phone ?

Thank you.

Hi there and welcome to the forum! While I’m sure @robertCM will likely chime in here at some point, I’ll share some important info for you since I have some prior experience dealing with Ringo and SIM modules/compatibility.

First off, you might want to check out this topic, as we take a pretty deep dive into all the different SIM modules and how they relate to region and carrier/frequency compatibility:

You need to find out what bands/frequencies your cellular carrier of choice uses, as the SIM7600 comes in multiple variants that support different groups of bands based on region. You can see a comparison chart of all the SIM7600 variants available here:

Here are charts of global cellular bands/frequencies:
UTMS(3G): https://en.wikipedia.org/wiki/UMTS_frequency_bands
LTE(4G): https://en.wikipedia.org/wiki/LTE_frequency_bands

For example, the SIM7600A only supports some of the 4G bands (AT&T, but not Verizon or T-Mobile) but includes 2G/3G support (most carriers have crap 2G/3G service in the USA; they’ve all but abandoned it). The SIM7600NA, on the other hand, supports almost all of the 4G bands, but has NO 2G/3G support. So, you need to identify exactly which variant you want based on which technologies and bands you need. All current generation SIM7600 variants end with a -H; only the one or two letters after the 7600 change.

Once you know which module you need, you can find it on TechShip.com. You need the mPCIe form factor. Usually, these types of components are bought in large bulk qty, but TechShip offers single unit purchasing for very reasonable prices. You’ll spent between $45-60 on TechShip.com, which is one of the cheapest sites I found that carries all the variants on one site…that may seem high, but you are asking to buy one of something that is usually sold by the hundreds or even tens of thousands in non-retail bulk packaging. A lot of other sites will sell only one or two of the variants below, but will charge $80-160 each for individual units. So TechShip.com is the way to go.

SIM7600NA-H (North America/USA targeted; wide 4G support; NO 2G/3G support) - $45

SIM7600A-H (North America/USA targeted; limited 4G support; YES 2G/3G support) - $49
(NOTE: Make sure you get the model that says “Audio interface: Digital PCM”…do NOT get the Analog signal version!!)

SIM7600E-H EU (Europe targeted; YES 2G/3G support) - $58
(NOTE: Make sure you get the “EU” model, NOT the “SIM” model!!)

SIM7600G-H (Asia/Australia/Africa/APAC…Global, basically; YES 2G/3G support) - $53

SIM7600SA-H (South America/Australia targeted; YES 2G/3G support) - $50

That having been said, I believe the fine folks at CircuitMess are willing to swap SIM modules with you (you return the SIM800C to them, they ship you a SIM7600x), but they only have the A (North America/limited 4G w/2G&3G), SA (South America/Australia), and E (Europe) variants available to send out. @robertCM can speak with you directly if you need one of those variants.

I hope that helps. It’s a bit to take in, but I just saved you the 2 months of homework I had to do in the beginning of my Ringo adventure to figure out why I had such crap connectivity and which SIM I really needed to have for best results in my ‘corner’ of the world.

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So, I have to admit that I hadn’t ordered anything from TechShip yet. It appears they do B2B only (no direct consumer sales), which partly explains the low price point. I’m registering my company with them so I can order a couple modules.

Assuming they let me into their little club, I could probably resell a module to you (at pure cost, no markups) if you need a variant other than what CircuitMess can provide. Even the additional shipping charges would likely still total to less than what most consumer-facing stores will sell one of these modules for; I’ve seen some sites selling SIMCOM modules for upwards of $160 each! Highway robery. :expressionless:


I am speechless for this detailed explanation :open_mouth:

I am from Greece so i want the europe version.
I will keep both so if i have some problem i will change them again.

Do you know if i must change the firmware too or the mainboard ?( for the new module )?

Awesome… @robertCM will likely be able to arrange for you to get a SIM7600E from them easier than dealing with TechShip and cheaper than dealing with a consumer facing retailer of SIMCOM modules. You’d also have peace of mind knowing it’s the exact version of the SIM7600E that works with the Ringo.

You won’t need to deal with any firmware or mainboard changes. You will, however, need to be sure to connect the antenna line to the correct connector on the SIM board. They use the same board design for multiple SIMCOM chipsets. You’ll read across the edge of the board two lines (one above the 3 connectors and one below) that start with model numbers (####). Just find the line that includes 7600 and read across to the right until you find MAIN and connect to that one.

(NOTE: The SIM7600E you receive may be different than this one, so don’t just assume it is the right-most connector from this image alone.)

Unfortunately, you cannot just swap modules, as I’m sure Robert will confirm. I’ve been there and done that and the main boards for the SIM800 and SIM7600 are physically different. At the very minimum, the SIM7600 modules require audio amplifier circuitry on the main board, whereas that audio amplifier is internal to the SIM800. There are other less obvious differences too, such as beefier power connections to the module. So your original suspicion that the entire phone must be replaced is true. They originally wanted to design the main board to accommodate either module but that never came to pass (unless something has changed in the past year).

Actually, there are several variants of each SIM7600x…usually at least one with Digital PCM Audio and one with Analog audio output.

In the latest firmware (MakerPhone.cpp), I see software based compensation on audio input/output depending on which module it detects:

if (sim_module_version == 1)
		Serial1.begin(9600, SERIAL_8N1, 17, 16);
		pinMode(17, INPUT_PULLUP);
		micGain = 14;
	else if (sim_module_version == 0)
		Serial1.begin(115200, SERIAL_8N1, 17, 16);
		pinMode(17, INPUT_PULLUP);
		micGain = 1;
if (buttons.released(BTN_UP) && callSpeakerVolume < 5)
			if (sim_module_version == 1)
				Serial1.printf("AT+CLVL=%d\r", callSpeakerVolume * 20);
			else if (sim_module_version == 0)
				Serial1.printf("AT+CLVL=%d\r", callSpeakerVolume);
			written = -1;
			tft.fillRect(56, 111, 20, 15, TFT_RED);
			tft.setCursor(59, 109);

So, maybe a mainboard swap isn’t needed if the correct audio type variant of the SIM7600E is used. I guess we’ll need @robertCM to confirm the current situation here.

I believe the issue was that the SIM7600* modules with audio output do not output a sufficiently strong signal to directly drive the speaker, while the SIM800 module does. If you look at the respective main-board schematics, you’ll see an audio amplifier chip (and supporting components) on the SIM7600 main-board that is not on the SIM800 main-board. It’s like the difference between a line-level output and a speaker/headphone level output.MakerphoneSchematics.zip (175.0 KB)

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He there,

Yes, @frankprindle is right, unfortunately you cannot just swap the modules. :confused:

That was the original plan, but unfortunately we weren’t able to do it due to the issues that Frank already mentioned (he has really done his homework!). :confused:

I also replied to your email @Petros, and the answer is no.

Is the 2G version not working properly in Greece?


Yes of course is working but i wanted to have a newest technology for the SIM module. :grin:

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Why not purchase a second Ringo and request that they send you a SIM7600 model? It’s not a terrible investment for what you are getting and you could always salvage some parts from the SIM800 unit if you needed to down the road…only a few things, like Frank mentioned, are different…many other parts could be desoldered and used in other projects or as replacement bits for the 7600 model as they wear out. 🤷 I see a perfectly good LCD, battery, buttons, LEDs, etc that would easily fit in other projects. haha

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Yes maybe :thinking: i will do that :wink:

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Your logic seems good, but in this case, you will really have no additional features on your phone.

The only reason we’ve even included the 4G version is that is some of the countries the 2G has been shot down. In most of the countries, 2G works a lot better than 4G, because you can cover more ground with fewer antennas. :slight_smile:

Of course, if you want to get another one that is 4G just for one, it’s a non-issue!

I’ll even hook you up with a little discount since you already own one. :wink:


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@TheWebMachine did you ever end up getting a SIM7600NA-H? Although Ting has been working well for me in my area, I received an email from them today:

We’re reaching out to warn you that the major US carriers are on the verge of shutting down their older networks in favor of newer LTE and 5G networks.

From January 2021, older devices including your SIM7600A-H lack the Voice over LTE (VoLTE) technology to connect over these newer networks and will stop working completely with most carriers. Your device could begin to experience issues even sooner.

We realize that this is a difficult time for unexpected expenses. But, at a time where staying connected is more important than ever, the last thing you want to worry about is issues with your service.

We recommend upgrading as soon as possible to avoid service disruption.

It appears that the 7600A-H will no longer work starting January 2021.

I did get one from them, but had very similar issues, mostly because signal is just that crappy here. A testiment to how horrible cell companies are in the US, since I live in a TOTALLY flat state that should have signals flying far and wide without issue. 🤦

That said, if your issues are with signal, given the announcement about VoLTE, the only way a modem swap makes sense now if is you are absolutely certain you get excellent LTE coverage where you are at. VoLTE is even MORE sensitive to crap signal, so if you have it bad now, it could get way better but could remain just as crappy regardless of modem.

I’ll need a few weeks if you still want me to broker you one. I’m in the middle of moving, so I don’t want to arrange shipping on anything until that is settled.

Thanks for the response TWM! My area does appear to have good coverage from 2G thru 5G, which is why I was hopeful the 7600NA-H module would work. I was curious if the module swap required any changes to the Ringo firmware, but it appears from your response that it should work just fine and is mostly dependent on service in the local area.

Robert also contacted me regarding this and it seems that CM may be able to sell me a 7600NA-H which should save you the trouble of brokering one to me. I’ll keep you posted, in the meantime I wish you the best of luck with your move :-)!

Thanks so much. I live in Japan and have built 2 units with no connectivity success. Now I know why. Thanks for helping :+1::+1: