Reference Table

/IOTCONNECT™
Reference Table

Quick reference for message types, error codes, authentication types, supported data types, and acknowledgment statuses used in the /IOTCONNECT™ SDK Protocol 2.1.

Message types

ct Value Type Direction Description
0 Device Command C2D Standard command from portal to device
1 OTA Command C2D Firmware update notification
2 Module Command C2D Module-specific command
116 Template Attribute Change C2D Template attributes modified
117 Template Settings Change C2D Shadow/twin properties changed
118 Rule Change C2D Rules updated
119 Device Change C2D Device config modified
120 Password Change C2D Credential rotation required
121 Hard Stop C2D Immediate disconnect instruction

Error codes

Code Message Context
0 Success All APIs
1 Invalid CPID/SID Discovery
2 Company not found Discovery
3 Subscription expired Discovery
4 Device not found Identity/Hello
5 Device not active Identity
6 Device blocked Identity
7 Template not found Identity

Authentication types

Code Auth Type Description
1 Symmetric Key Shared access key authentication
2 X.509 (Self-signed) Auto-generated device certificate
3 X.509 (CA-signed) Certificate signed by registered CA
4 TPM Hardware security module authentication

Supported data types

Type Description Example
INTEGER Whole numbers 25, 100, -10
LONG Large integers (64-bit) 1234567890
DECIMAL Floating point numbers 25.5, 99.99
STRING Text values “active”, “ON”
BIT Binary (0 or 1) 0, 1
BOOLEAN True/False true, false
DATE Date only “2026-06-19”
DATETIME Date and time “2026-06-19T10:30:00Z”
LATLONG Coordinates “23.0225,72.5714”
OBJECT Nested structure {“lat”: 23.5, “lng”: 72.6}
ARRAY List of values [1, 2, 3]

Acknowledgment statuses

Command Acknowledgment:

Status Code Description
Failed 4 Command execution failed on device
Executed 5 Command executed but result unknown
Success 6 Command executed successfully

OTA Acknowledgment:

Status Code Description
Downloading 1 Firmware download in progress
Downloaded 2 Download complete, ready to install
Success 3 Firmware applied successfully
Failed 4 Update failed (download or install)