33: SIM settings

For devices that have dual-sim functionality, control which SIM is active and set APN parameters for SIM2

Header

Field	Name	Description	Type
5	Method	Request a service to be perform an action Possible values: 1: SET— Set one or more values that are provided in the message payload. 2: GET— Get values for the associated message type. 3: SUBSCRIBE— Subscribe to values for the associated message type. Can be used in conjunction with other header fields to define the subscription parameters, such as Interval, Duration, Timeout, Storage Level and Message Level. If no interval is provided, messages will be sent as and when new data is available. Some data, such as GPS position, may require a set interval to be provided. 5: UNSUBSCRIBE— Unsubscribe from a previous subscription.	uint8

This is an extract of header fields that are relevant to this message type, you can find them all documented in the Headers section.

Payload

Field	Name	Description	Type	Unit
1	Active SIM	Activate the specified SIM If SIM2 is selected, sending the APN settings is required Possible values: 0: SIM1 1: SIM2	uint8
2	SIM2 APN		ascii
3	SIM2 APN Username		ascii
4	SIM2 APN Password		ascii
8	SIM2 ICCID	SIM2 ICCID if known, read-only. This value may be cached from a previous read and stale.	ascii

Examples

Enable SIM2 with APN settings

Protocol

3

3

Length

420

42 bytes

Type

330

33 (SIM settings)

Header Count

20

2

Header Types

15

1, 5

Message ID

422000

22

Method

11

1 (SET)

Payload Count

20

2

Payload Types

12

1, 2

Active SIM

41000

1 (SIM2) (expected 1 bytes, got 4)

SIM2 APN

141151111091014697112110461121089799101

some.apn.place

Checksum

85240

61525

📡 Real example from Generate tool on 2025-10-15Created using the generate tool, this was tested against an RH2 device, sent from Toit.

ACK SIM2 settings

Protocol

3

3

Length

240

24 bytes

Type

50

5 (ACK)

Header Count

20

2

Header Types

34

3, 4

Response to

422000

22

Status

10

0 (OK)

Payload Count

10

1

Payload Types

1

1

ACK Type

2330

33

Checksum

3672

18468

📡 Real example from RH2 P1 v2296 on 2025-10-15This example is captured from an RH2 device as part of normal communications over I2C with the ESP32 co-processor, in response to the previous message.

GET request for SIM settings

Protocol

3

3

Length

200

20 bytes

Type

330

33 (SIM settings)

Header Count

20

2

Header Types

15

1, 5

Message ID

423000

23

Method

12

2 (GET)

Payload Count

00

0

Checksum

123128

32891

Code

For convenience, the following constants can be used to reference this message type.