Reception Confirmation (ACK)

When the server receives a report from the device, it must respond with an ACK (acknowledge) to confirm correct reception.

📋 ACK Format


>ACK;#NNNN;ID=XXXX;*CC<

Field	Description
`ACK`	Confirmation command
`#NNNN`	Message number of the received report (hex)
`ID=XXXX`	Device ID
`*CC`	Checksum


>RCY00020205000000-2778467-06425658000000-000090;DFFFFFF;IGN1;IN00;XP00;#0021;ID=1234;*59<


>ACK;#0021;ID=1234;*72<

The #0021 must match exactly with the report message number.

To respond from a mobile phone to an SMS report, the short version can be used:


>ACK;#0021<

Without ID or checksum, but maintains the message number.

If the device doesn’t receive ACK:

Step	Action
1	Stores the report in buffer (BlackBox)
2	Retries sending
3	After several attempts, switches to secondary IP

The server can send commands with message number (range 0x8000 - 0xFFFF) to receive confirmation from the device.

Server sends:


>SSSXP0011;#8001;ID=1234;*6A<

Device responds:


>RSSXP0011;#8001;ID=1234;*6B<

The response with #8001 confirms that the command was executed.

Range	Origin	Use
`0x0000` - `0x7FFF`	Device → Server	Automatic reports
`0x8000` - `0xFFFF`	Server → Device	Commands with confirmation

The checksum (*CC) is calculated by performing XOR of all characters from > to * (not including the *).

👉 Use the Checksum Analyzer to calculate and verify checksums.