As SGP.32 and the IoT Profile Assistant (IPA) gain traction in the eSIM world, more deployments are relying on eUICCs (embedded SIM cards) that can autonomously initiate remote SIM provisioning. For that to work, many eUICCs require the ability to open a TCP/IP channel via the device’s modem, known as Bearer Independent Protocol (BIP).

While nearly all modern IoT modems released in the past five years support this functionality, we continue to see real-world challenges where the modem doesn’t have BIP or STK (SIM Toolkit) properly enabled by default—which can block eSIM provisioning entirely.

If you’re new to eSIM for IoT, check out our Simplex eSIM overview page to learn how our architecture is built around SGP.32, multi-carrier support, and global scalability.

A Real-World Example: ChatGPT Helped—Until It Didn’t

At Simplex Wireless, we often leverage tools like ChatGPT to speed up device configuration and troubleshooting. In fact, we even wrote about it earlier this year in our guide:
How to Enable BIP/STK on Modems for eSIM IoT SGP.32 Deployments

But recently, we hit a frustrating roadblock while trying to get BIP/STK working on a Quectel EC25G modem embedded in a cellular router.

ChatGPT initially recommended the following command to enable STK:

AT+QSTK=1

The logic appeared sound. On some Quectel modules, this command is used to manually activate proactive commands—such as triggering a tone, menu item, or network command—via the SIM Toolkit. However, what ChatGPT missed was that SGP.32’s IoT Profile Assistant expects the modem to automatically respond to eUICC commands without any manual trigger from the host.

This misunderstanding caused a delay of several weeks as we debugged the issue.

The Correct Configuration for Quectel EC25G (and Similar)

What was actually needed to enable automatic BIP functionality was a different set of commands entirely:

AT+QSTK=0

AT+QCFG="bip/auth",0

Here’s what these commands do:

• AT+QSTK=0: This disables manual STK triggering, allowing the SIM card to operate in automatic mode.
• AT+QCFG="bip/auth",0: This disables BIP authentication, enabling the SIM to initiate the TCP/IP channel automatically via the modem.

This configuration effectively allows the IPAe (IoT Profile Assistant embedded) on the eUICC to open the BIP channel, complete remote profile operations, and interact with the EIM (eSIM IoT Manager) without needing host-side intervention.

To learn more about how our in-house EIM platform supports SGP.32-based eSIM management, visit our product overview page.

Why This Matters for SGP.32 IoT Deployments

As more enterprises adopt SGP.32-based eSIM solutions, understanding how to configure modems correctly is crucial to deployment success.

A growing number of eUICCs now require the ability to initiate BIP sessions autonomously to fetch profiles or update connectivity. If your device doesn’t support BIP—or the modem is misconfigured—eSIM provisioning may silently fail, and you’ll end up troubleshooting symptoms rather than root cause.

If you’re sourcing devices and need SIMs that support Cat-M1, Cat-1 BIS, fallback LTE, and advanced eSIM workflows, check out our IoT SIM card product page or request a trial SIM.

Lessons Learned

Here’s what this experience taught us—and what we recommend to any team deploying IoT devices with eSIM:

• Don’t assume default modem firmware enables BIP/STK. Even modern modules like Quectel EC25G may need additional configuration.
• Be cautious with AI-generated AT command guidance. ChatGPT can be a great assistant, but verify its responses against module documentation or real-world tests.
• Enable automatic mode. For eSIM profile management via SGP.32, ensure your modem is set to allow the eUICC to autonomously initiate BIP.
• Keep a configuration checklist. When deploying at scale, a tested set of AT commands can prevent weeks of troubleshooting per device.

We also recommend reviewing our IoT Glossary if you’re new to terms like BIP, STK, or eUICC.

At Simplex Wireless, we’re committed to helping our customers simplify and scale eSIM deployments, especially under the SGP.32 framework. Whether you’re dealing with STK/BIP, modem firmware, or eUICC compatibility, our team has the real-world experience—and lessons learned—to help you get it right.

Ready to simplify your SGP.32-based IoT deployment? Contact us today and let’s build it right the first time.

This article was written 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