KA Command - Multi-Destination Keep Alive

Sends periodic KA messages to maintain active connections with servers. Supports main server, backup server, or both simultaneously.

Works automatically with WiFi and GPRS according to channel configuration.

📋 Syntax

Configure (SKA)


SKA[time],[destination]

Parameter	Description
`time`	Interval in seconds (0-3600, 0=disable)
`destination`	`B` = Backup, `M` = Main, `BM` = Both (optional, default: B)

Query (QKA)

QKA

Response:


RKA[time],[destination]

🎯 Destinations

Value	Server	Description
`B`	Backup	Send only to backup server (default)
`M`	Main	Send only to main server
`BM`	Both	Send to both simultaneously

💬 Examples

Configure Keep Alive


>SKA60,B<       // 1 min to BACK
>SKA120,M<      // 2 min to MAIN
>SKA180,BM<     // 3 min to both
>SKA60<         // 1 min to BACK (default)
>SKA0<          // Disable

Query configuration


>QKA<

Possible responses:


>RKA60,B ...    // 60s to BACK
>RKA120,M ...   // 120s to MAIN
>RKA180,BM ...  // 180s to both

📌 Use Cases

Scenario	Command	Interval
High availability	`>SKA60,BM<`	1 min to both
Main only	`>SKA120,M<`	2 min
Backup only	`>SKA30,B<`	30 sec
Critical connection	`>SKA10,BM<`	10 sec to both
Data saving	`>SKA600,M<`	10 min
Disable	`>SKA0<`	-

⚙️ Features

Feature	Description
Interval	1-3600 seconds (0=disable)
Message sent	`KA`
Connectivity	Automatic WiFi/GPRS
Persistence	Configuration survives restarts
Redundancy	Two simultaneous servers with `BM`
Failover	Automatic between servers

Maintains active connections on networks with aggressive timeout (NAT, firewalls).

Compatibility

ZE-IoT

SP-IoT

SM-IoT