eSIM RSP Knowledge Base

Comprehensive technical knowledge base covering 12 GSMA eSIM specifications. 84+ articles on Remote SIM Provisioning — SGP.02, SGP.22, SGP.32, SGP.41, SGP.29, SGP.23, SGP.25, SGP.26 and more.

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The Chip Test Lab: Readers, Probes, and Poking Tools 🔬🔌

Imagine…

You’re testing a tiny computer chip the size of a grain of rice. You can’t plug a keyboard into it. You can’t connect a monitor. All you have are five tiny metal contact pads: and a very precise testing machine that sends electrical signals and measures the responses.

This is the world of eUICC test architecture : where special card readers, USB probes, and five different simulator programs work together to poke and prod every corner of the chip.

Two Ways to Connect 🔌

The chip can be tested in two physical forms:

Test Setup	How It Connects	Used For
TE_eUICC	Metal contacts via a PC/SC card reader	Standard removable chips (like Java Cards)
TE_Integrated eUICC	USB CCID test cable in “card reader mode”	Chips buried inside phone processors

For the integrated chips, it’s actually clever: the chip pretends to be a smart card reader over USB! The test tool plugs in and talks to it as if it were a card reader with a chip inserted.

The Five Simulators 🤖

Since ONLY the chip is real, five different simulator programs pretend to be everyone else:

Simulator	Role	What It Sends
S_Device	Phone/modem	ISO 7816-4 APDU commands: the same electrical signals a real phone sends
S_LPAd	Phone Assistant	ES10 commands wrapped in STORE DATA envelopes, sent on a special channel
S_SM-DP+	Key Maker	Bound Profile Packages, certificate chains, authentication challenges
S_SM-DS	Post Office	Event records for discovery testing
S_MNO	Mobile company	Over-the-air commands for ES6 testing

The Secret Channel System 🚪

The chip uses a clever two-channel system, like a hotel with a front desk and a VIP entrance:

Basic Logical Channel : For normal phone commands: “Hello, are you there?”, “What are your capabilities?”, “Reset yourself”
Dedicated Logical Channel : Opened by the LPA simulator specifically for ES10 profile commands: “Get profiles list!”, “Download this key!”, “Enable that profile!”

This separation means the profile management commands can’t accidentally interfere with normal phone operation: and vice versa.

How a Test Actually Runs ⚙️

Every test case follows the same recipe:

Set initial conditions : The chip must start in a known state (certain profiles loaded, certain certificates present, certain mode enabled)
Follow the numbered steps : Each step says exactly who sends what command and what response to expect
Check the results : Every response must match the expected data, down to the status word (SW=0x9000 means success!)

The test scripts use a three-tier notation system:

#CONSTANTS : Fixed values like #ISD_R_AID (the chip manager’s ID)
<VARIABLES> : Dynamic values like <EUICC_CHALLENGE> (a fresh random number)
#IUT_SETTINGS : Vendor-specific details like #IUT_MEP_LSI_OPTIONS

The Known Starting State 📍

Before testing begins, the chip must arrive in a carefully prepared state:

Test certificates and keys are pre-loaded (NOT real GSMA certificates!)
PROFILE_OPERATIONAL1 is installed (usually disabled)
The Rules Authorisation Table is configured for the right mode
A clean-up procedure can reset everything between test runs

This means every test starts from the same known point: like resetting a video game to level 1 before each new player tries.

For MEP (Multiple Enabled Profiles) testing, the Device Simulator has to support two different ways of telling the chip “now talk on this line” : either through MANAGE LSI commands or through a special byte in the T=1 protocol. The chip maker declares which method their chip uses, and the test adapts!

Kid-friendly version of GSMA SGP.23-1, Section 3, Annexes A, E, F, G, J

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