Wireless Joint

Hello everyone, cool site you have here. Apologies in advance if this post is in the wrong thread, i'm a bit of a novice with this sort of thing. For many years, i've operated a 32 Port 3G GSM Modem Pool device. It looks like this.
I connect it via USB to my Windows machine and run specialized SMS software to communicate with the device. I can set up connectors to, for example, forward all incoming SMS messages to an email address with a specific template. It's pretty nifty.

Anyways, the device has started to have some issues, and with the impending shutdown of many 3G networks, I figured it was time to update to a 4G LTE compatible device.

The product i'm looking at is:
https://www.alibaba.com/product-detail/ ... 71d2nl2rvw

Aside from 3G to 4G, it seems like the main difference between this new device and my old one is that the new one is more of a self-contained server, which plugs directly into Ethernet, and then lets you access it via it's IP address on the LAN.

The vendor says they can provide it with an EC25-AF chip, which, according to my quick research, should be compatible with T-Mobile, AT&T and Verizon in the US. Is that correct? And does anyone have experience with this sort of device, anything I should know before purchasing one?

The EC25AF will in fact work after the 3G sunset as long as you set each modem to "Data Centric" and have it's latest firmware.

Wether or not ATT themselves allow the imei of the modems direct to account is a different subject.


What do you use this particular setup for? Mass texting, or other uses? Pretty cool.

Didneywhorl wrote: Tue Oct 12, 2021 6:57 am The EC25AF will in fact work after the 3G sunset as long as you set each modem to "Data Centric" and have it's latest firmware.

Wether or not ATT themselves allow the imei of the modems direct to account is a different subject.


What do you use this particular setup for? Mass texting, or other uses? Pretty cool.

I've been told that IMEI concerns are not an issue. And in the past, if I ever had issues with particular SIMs in my old 3G modem pool, I would just plop the SIM into my iPhone to let it activate, and then it would work fine in the modem pool.

No, not mass texting, I use this setup because it allows me to simultaneously operate multiple mobile numbers. I buy and sell stuff on Craigslist and other sites, and so being able to maintain separation between my actual cell number and clients is very helpful. Every once in a while you deal with a crazy and have to burn a particularly number, so I can easily just swap in a new SIM. I use this in conjunction with the cheapest compatible MVNO provider I can find--used to be Ultra Mobile's PayGo plan at $3/month, though i've read recently that U.S. Mobile has an even cheaper $1.50/month plan.

Now on to a little wrinkle...the Chinese supplier of this device is now telling me that there's an EC25-AF chip shortage, and that I would have to wait a long time to get a device with that module, but they can instead provide me a device with either EC25-AFX or EG91.

I pulled the EC25 specification sheet directly from Quectel's website:
https://www.quectel.com/wp-content/uplo ... n_V2.1.pdf

It appears to be version 2.1 of the specification sheet and shows the following:
It clearly shows the EC25-AFX as only supporting Verizon or AT&T (FirstNet) in North America.

The Chinese supplier of the device is telling me that I have an outdated version of the EC25 specification sheet, and the EC25-AFX now supports Verizon, AT&T and T-Mobile in North America.
I'm not sure what to believe here. Anyone have any further insight?

As for the EG91 chip, the specification sheet directly from Quectel does show that the EG91-NA model is certified for Verizon/AT&T/T-Mobile in North America. I see that it's LTE Cat 1 as opposed to the EC25 which is LTE Cat 4, but as i'm not using data, that's irrelevant to me.
So...anyone know if the EC25-AFX actually supports AT&T, T-Mobile and Verizon as the Chinese supplier is claiming?

And if the answer is that they are incorrect and the EC25-AFX does not support AT&T, T-Mobile and Verizon, is there any downside to going with the EG91-NA (aside from slower data)?

The EC25AF and EC25AFX are both supported, based on the bands, but the firmware may or may not be certified. Though it usually doesn't matter unless the carrier says yea or nay to the imei.

The only difference between the AF and AFX is the AFX doesn't support voice. Data only. I have personally used the EC25-AFX on T-mobile, Verizon, and ATT. BUT! Not registering the device and imei directly to the account. I SIM swap A LOT.

If you aren't looking for much data use the catM and cat1 modules may be a better/cheaper bet anyway.

@ loxers912
Want to sell your old modem block device?

We shouldn't forget the impending ATT IMEI whitelist in 2022