It is very common that our customers have IoT devices that they have sources from outside the US and they have received the incorrect hardware configurations for the US. As IoT devices are inherently low cost they will use Modems (Modules) that are region specific, US, EUROPE, APAC. An IoT device designed for Europe will have very limited support in US and will work sporadically based on location.

One of the lesser-known — but critically important — factors to consider is the radio access method used by cellular networks: FDD (Frequency Division Duplex) vs. TDD (Time Division Duplex). North America, including the U.S. and Canada, predominantly uses FDD-based LTE bands, while many parts of Asia (notably China) and some European networks also deploy TDD bands like Band 38, 39, 40, and 41. This divide matters because many lower-cost IoT modules are built for regional markets and might only support TDD bands, rendering them incompatible with U.S. networks like AT&T, Verizon, or T-Mobile. At Simplex Wireless, we’ve seen many global customers run into this roadblock — often after importing hardware that looks great on paper but doesn’t support the right duplexing modes or frequency bands for North America.

Step 1: Understand the Key U.S. LTE Bands

The first step is knowing what you’re looking for. The major LTE and LTE-M bands used in the U.S. are:

• Band 2 (1900 MHz) – Used by AT&T and T-Mobile
• Band 4 (AWS 1700/2100 MHz) – T-Mobile, Verizon, AT&T
• Band 5 (850 MHz) – All major operators
• Band 12/13/17 (700 MHz) – Used by AT&T (Band 12/17) and Verizon (Band 13)
• Band 66 (AWS-3) – T-Mobile
• Band 71 (600 MHz) – Primarily T-Mobile
• Band 26 (850 MHz) – Sprint/Verizon legacy

For LTE-M (Cat-M1) and NB-IoT, U.S. coverage is dominated by:

• LTE-M: Supported by AT&T, Verizon, and T-Mobile
• NB-IoT: T-Mobile only

You can ask ChatGPT:

“Does the Quectel BG95-M3 support Band 13 or Band 12? Will it work on Verizon in the U.S.?”

ChatGPT will review the module’s spec sheet (if known) and check if it aligns with Verizon’s required LTE bands.

Step 2: Match the Device Modem Against U.S. Carriers

Whether you’re working with a Teltonika RUT241, a Quectel BG77, or an obscure brand from Alibaba, you can ask ChatGPT to:

• Break down which LTE bands the device supports
• Cross-reference them with AT&T, Verizon, and T-Mobile’s network requirements
• Highlight whether the modem includes fallback features (Cat-M, 2G fallback, roaming capabilities)

You might ask:

“Will this GPS tracker that supports Cat-1 Bands 3/7/20 work in the U.S.?”

ChatGPT will likely respond:
“No, because Band 3 and 7 are common in Europe/Asia, and Band 20 is not used in North America.”

Step 3: Evaluate LTE Cat Type and Future-Proofing

Simplex recommends using Cat-M1, Cat-1 BIS, or Cat-4 modems for U.S. IoT deployments. We’ve previously explored RedCap (Reduced Capability 5G) for future projects, but today, it’s limited to T-Mobile trials and not yet widespread across AT&T or Verizon.

You can ask ChatGPT:

“What’s the difference between Cat-M1 and Cat-1 BIS for IoT GPS tracking?”

And get guidance on power consumption, uplink/downlink speeds, module pricing, and regional support — helping you choose the right technology for your use case.

Step 4: Use Real-World Queries to Simplify Workflow

One of our team members has used ChatGPT to:

• Verify if a Teltonika RUTX12 with dual LTE modems can be used in Canada and the U.S.
• Determine fallback behavior if the preferred band isn’t available
• Compare modules like Quectel BG95-M3 vs BG95-M1 vs BG77

This kind of exploration saves hours of data sheet hunting and makes early-stage validation faster and more productive.

Conclusion: ChatGPT as a Fast, Flexible IoT Validator

ChatGPT isn’t a replacement for testing or certification, but it’s become a powerful assistant for the Simplex team when evaluating global hardware for U.S. deployments. By using it as a quick lookup tool, we’ve accelerated hardware onboarding and better supported customers using our global eSIM and data connectivity.

If you’re looking for flexible, BYOO-compatible IoT SIMs or help validating your device’s modem setup, reach out to Simplex Wireless. We’re happy to support your path to scalable IoT — no matter what module you’re using.

This article was curated by Jan Lattunen, CCO Simplex Wireless

About the Author: Jan Lattunen manages Sales and Marketing for Simplex Wireless. Jan has 20 years’ experience in working with SIM card technology and was involved in launching the eSIM in North America with major carriers and OEMs. His expertise in telecommunications is around SIM cards. On a personal note, Jan is a family man and avid cyclist with advocacy for safety in the roads. You can connect with Jan on https://linkedin.com/in/JanLattunen