Board Versions
An important thing to know when buying the LTE CAT-M/NB-IoT shield is which one to choose! The first thing to note is that the shield doesn't operate on traditional LTE but uses LTE CAT-M which is based on the existing LTE networks but the networks must support LTE CAT-M1 in order for the shield to work with that mode. However, SIM7000C and SIM7000E versions can also "fall back" to 2G or 2.5G as appropriate. The shield comes in three version to cater to different parts of the world using the following SIM7000 module variations:
Recently (as of March 2018) SIMCom has been distributing the SIM7000A in two versions, the SIM7000A-A for AT&T and the SIM7000A-V for Verizon. To my understanding they can only be PTCRB (carrier-certified) for a single carrier and not both AT&T and Verizon for some reason, so they split it up like this. However, they will still work on both networks. For example, if you bought SIM7000A-A it shoud work on Verizon but it has a preference to AT&T. Before this change the SIM7000A has worked with both networks just fine!
Generally speaking the suffix denotes the region. For example, "A" for "American", "C" for "Chinese", "E" for "European", and the "G" is for "Global" (basically all the previous versions combined into a single module!). These regions are called ITU regions and correspond to the highlighted geographical areas shown in the map below:
Photo credit: Map above is from en.wikipedia.org
So generally speaking, if you live in US or Canada you would choose the SIM7000A; if you live in the Netherlands you would select the SIM7000E, and so on. However, you should further also make sure that you have LTE CAT-M1 or NB-IoT coverage in your area by checking with the operators in your area because the SIM7000 does not operate on traditional LTE, although CAT-M does use existing LTE infrastructure. The following map shows some major operators that support CAT-M1 or NB-IoT or both, as of June 2017:
Photo credit: Map above is from www.qualcomm.com
It should be noted that the SIM7000A version only supports LTE CAT-M1 and NB-IoT, whereas SIM7000C and SIM7000E are backward-compatible with 2.5G (EDGE) and 2G (GSM/GPRS).
After determining if you have CAT-M1 or NB-IoT coverage in your area you should also further investigate the LTE bands that are used in your area. You can do this by going to this handy frequency checker and selecting your country, then scrolling down to the "LTE" list. For example, the LTE bands used in the United States are shown below:
Please note that different cell carriers use different bands, so only the LTE CAT-M ones might be relevant. For example, in Australia Telstra uses bands B3 and B28 for LTE (with CAT-M support) but other carriers may not have CAT-M support, so even though you might see other bands appear in the website's list, the SIM7000 module might not operate on them because those particular bands may not have CAT-M.
Looking at the specs of the SIM7000-series modules we see that the various SIM7000 versions support the following bands:
- SIM7000A: B2/B4/B12/B13
- SIM7000C: B1/B3/B5/B8
- SIM7000E: B3/B8/B20/B28
What you should now verify is whether the supported bands of the module match with the LTE bands used in your area and double-check if they're also CAT-M. In our same example, in Australia Telstra uses B3 and B28 and supports CAT-M1 and therefore the SIM7000E would probably be most appropriate since it supports both of those bands.
There are inherent differences between the two types. I am not going to write an essay about what those differences are and I don't claim to be an expert on them but here is what I understand:
LTE CAT-M1:
- Uses the existing LTE infrastructure so it's easier for carriers to implement
- Uses less bandwidth and therefore less power than traditional LTE CAT-1, 3, 4, 6, etc.
- Has transfer speeds of about 3x that of NB-IoT
- Has great mobility and supports hand-over and therefore is suitable for asset tracking, fleet management, etc.
- Can support VoLTE (voice over LTE), unlike NB-IoT. However, this has yet to be implemented in the SIM7000 module
NB-IoT:
- Uses less power than CAT-M1 while sleeping, great for transmitting once in a while
- Also uses less bandwidth for very minimal data transmission
- Great building wall penetration
- Great for stationary equipment but not good for things like long-distance GPS tracking, etc.
- Has latency time that can vary up to 10s. Maybe not a good choice for time-sensitive alerts
Based on your needs you may want to choose one or the other! Not all countries support NB-IoT so you should investigate whether your country has it or not since I'm not aware of any "magic map" that shows exact coverage since many carriers are in the process of implementing it and it's rapidly changing. For example, in the United States T-Mobile announced that it will launch NB-IoT nation-wide sometime in 2018.
You can order any of the above versions on my website.
NOTE: This tutorial is meant to be supplementary information only and I leave it up to you to make the final decision on which version to order. I am not liable for any operation failure resulting in selecting an incorrect module and you are fully responsible for researching if this module will work for you! That being said, I do offer prompt technical support and try my best to resolve any issues. I can also pretty much guarantee that the SIM7000A version will work in the United States right away with my example code because it has worked on both AT&T and Verizon CAT-M1 networks flawlessly!