SIM Command — SIMcard Selection

Selects the active SIMcard in Dual SIM devices.

What is it for?

📱 Main use cases:

🔄 Switch between carriers based on coverage
💰 Optimize data costs by region
🌍 Automatic or manual roaming
🔧 Configure backup SIM
🛡️ Communications redundancy

When executing a SIM change, the following are automatically applied:

APN (CXAPN Command)
Carrier code COPS (COPS Command)
Security PIN (PIN Command)

A cellular modem reset is also executed to apply the changes.

Commands

Operation	Syntax	Response
Select	`SSIMa`	`RSIMa`
Query	`QSIM`	`RSIMa`

Parameters

Parameter	Description	Values
a	SIMcard number	`0` = SIM0 (default), `1` = SIM1

Associated Signals

Property	Value
Signal	`SIM`
Index	`00` - `01`
Conditional use	✅ YES

Examples

Switch to SIM1


>SSIM1<    // Switch to secondary SIM
>RSIM1<    // Confirmation

Query active SIM


>QSIM<     // Query which SIM is active
>RSIM0<    // Response: SIM0 active

Usage in rules (automatic change by zone)


>SRL50E;TRG=MC00+;ACC={SSIM1}<    // When entering country X, switch to SIM1
>SRL51E;TRG=MC01+;ACC={SSIM0}<    // When entering country Y, switch to SIM0

Compatibility

💾Firmware:v1.00.00

SPLegacy

ULLegacy

MTLegacy

SM-IOT