I am almost done installing my 2GIG alarm system. Only thing I have left is some kind of siren and the cellular chip. Both CDMA and GSM service work about the same in my area. Given, that is there a recommendation on which one is better or is it best to compare using a CDMA cell phone vs. GSM cell phone and looking at the signal strength… Thanks…

At this point you will want to be using either the Verizon CDMA or AT&T HSPA card. The 2G GSM cards will be phased out along with the infrastructure and support far sooner.

Go with 3G CDMA or HSPA modules, not the 2G GSM which are discontinued, carrier support ending.

Have you checked with If either is good it doesn’t matter as long as its 3G (Verizon or AT&T)

Verizon 3G CDMA cellular module: 2GIG-GCCDMV-A
AT&T 3G HSPA cellular module: 2GIG-GC3GA-A

3G Verizon CDMA modules are cheaper (approx $88),and 3G AT&T HSPA are approx $108

Check here:

As for siren, here is a zwave 100db Everspring/Utilitech zwave siren (get them at Lowes in iris section for $29)

One difference I have noticed between the CDMA and the GSM modules… the GSM modules have longer antennas that can be used. So if you’re in an area with weaker signals, you can use a better antenna with GSM. I haven’t seen any antennas (like in-wall, attic, etc) for the CDMA module.
Can anyone else confirm this?

I am looking to take over my vivint panel, and it already has the in-wall antenna, so I am going to get the more expensive GSM module, just so I can use the antenna.

All the CDMA and HSPA 3G antennas are “in the wall”

The GSM modules are less expensive because they are all discontinued, and soon will no longer work (GSM1-GSM7).

If you get a 2G (GSM) module, plan on replacing it with a 3G CDMA or HSPA module within the next few years or so

Info on the ATT and T-Mobile sunset:

RE: *GSM5; GSM6; *GSM7

AT&T said it plans to switch off every last bit of its 2G cellular network by January 1, 2017

AT&T 2G cellular ‘sunset’ in California and other US areas effective May, 2014.


T-Mobile plans to upgrade entire 2G network to LTE by mid-2015
  • Vivint locked GSM modules (as are CDMA “GCCDMV-V”, and HSPA “GC3GA-V”)

3G CDMA/HSPA “in the wall” antenna

I have a 2gig panel w/Verizon card. My father wanted a 2gig panel, so I went over his house armed with two iPhones 5S models - one Verizon, one AT&T. He had a mediocre Verizon signal, and an excellent AT&T signal - both with LTE and when I disabled LTE on the phone (HSPA+ on AT&T and EV-DO on Verizon).

Based on that test, I ordered him an AT&T 3G module for his 2gig panel. Surprisingly, the signal was really poor - like 6/30 on the alarm panel. The external whip antenna didn’t help. I then brought my panel over, and the Verizon signal was great despite the mediocre signal on my Verizon iPhone.

I’m not sure how to determine ahead of time which card will perform best. Both addresses are in an ‘Excellent’ area for both providers, but the AT&T phone gets no service whatsoever at my address.

I thought testing phones from both providers would help, but in this case it didn’t. The Verizon card seems to have better RF, or maybe the frequencies it operates on have better building penetration. I think the CDMA card wins if you have good service for both at your address, plus its cheaper.

Thanks for clarifying.

My current system has a vivint GSM/2G module with a 2-foot in-wall antenna (2GIG-ANT1X).

Do the modules bought from come with an antenna? I doesn’t specifically say, but I imagine, they must come with something.

Yes, the 2GIG CDMA and HSPA cell modules come with an in-wall antenna.


You determine which card will work best by doing a cellular module check:

As rive posted, check the coverage area for ADC service. Often the service you see on cell phone coverage by carrier does not correlate to which module will work better in your Go!Control panel. If the results show equally good service for multiple carriers at your service address, I personally recommend going with Verizon.

The coverage tool cited by rive is what prompted me to do the cell phone test.

Results for my address:

Verizon: Full Coverage
AT&T: Full Coverage
T-Mobile: Full Coverage

Now, at my house - even in the front yard - I get “No Service” on AT&T, I only get Edge (2G) with T-Mobile, and Verizon barely works - I use a Verizon network extender in the house. So I thought the ADC tool couldn’t be trusted. Thats why I started gathering phones to test it myself.

My dad’s address showed full coverage for each provider as well, but the Verizon card performed much better than the AT&T one 5-8 out of 30 with AT&T and like 15-20 out of 30 with Verizon.

The coverage check is nice but it’s done by zip code so isn’t accurate down to your specific location. It just tells you whether your zip code is reasonably covered by each provider.

There is a way to check for actual signal strength, probably not actual, but more reliable test than checking service strenght bar.
I carry to 2 iPhones 5s on me, one is personal(att-gsm) another from work(Verizon-cdma). I do the test by running “speedtest” app on both phones at the same time and compare results.
I’m not sure if it’s true or not, but I heard that “service bar” getting results from so called tower control channel and not the channel you’ll be on during actual connection.

Cellular signal strength for phones/tablet devices is not the same as that used for M2M cellular devices (like the 2GIG cellular modules for GPRS, HSPA, CDMA)

All GSM modules are no longer allowed by ADC for acct creation, and both the 2G TMO and ATT will very soon no longer even work as the M2M spectrums/frequencies they use are being reallocated.