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What is SIM toolkit? All you need to know

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  • 2 min read

Telecom carriers have come a long way in terms of the features and services they offer and their coverage. However, things have also improved on the user’s end with more options to configure their network connections how they want. 

In this article, we’re talking about what is a SIM toolkit, what it does and everything else you need to know. 

Also read: 5 types of SIM cards explained


SIM toolkits explained

SIM toolkits are generally programmed in the SIM card itself and are simply a set of commands or apps that control how a SIM card interacts with the device. The toolkit allows a SIM to drive the device’s network equipment interface, facilitate interaction between the network and the end user, and allow access and control to said network. 

It’s the standard of the GSM system, and the commands are standard for most mobile equipment as defined by the ETSI and 3GPP specifications. They also allow for value-added services and functionality that most telecom carriers offer to be built into the SIM card.

In a nutshell, a SIM toolkit allows the SIM card and any onboard applications to operate on and interact with a compatible device. 

Generally, SIM toolkits are implemented in three separate layers. 

  • RIL: Low-level software interface provided by the carrier.
  • SIM Toolkit (STK): Machine code that converts the information and data from the RIL layer to system-level messages that a smartphone or SIM-compatible device can understand.
  • User Interface: This is the app that we see on our phones that lets the users initiate action or manage access. 

Are SIM Toolkits safe?

SIM toolkits don’t usually have the best UIs and are buried in your phone settings if not visible as a separate app. This can make some users scared as to whether they’re malware. However, SIM toolkits are not only safe, but they’re also necessary if you want greater control over your SIM card and the add-on carrier services you use, if any. 

Also read: How to find SIM card number on iPhone?

Yadullah Abidi

Yadullah Abidi

Yadullah is a Computer Science graduate who writes/edits/shoots/codes all things cybersecurity, gaming, and tech hardware. When he's not, he streams himself racing virtual cars. He's been writing and reporting on tech and cybersecurity with websites like Candid.Technology and MakeUseOf since 2018. You can contact him here: yadullahabidi@pm.me.

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