LG M2900S-BN - Manual (Page 26)

OK Acknowledgement
[OK]
* The Product transmits ACK (acknowledgement) based on
this format when receiving normal data. At this time, if the
data is data read mode, it indicates present status data.
If the data is data write mode, it returns the data of the PC
computer.
Error Acknowledgement
[NG]
* If there is error, it returns NG.
Controlling the Multiple Product
RS-232C
A3
Transmission
[Command1][Set ID][Command2][Data][Cr]
* [Command 1]: First command. (j)
* [Command 2]: Second command.
* [Set ID]: Set up the Set ID number of product.
range : 00~99. by setting '0', server can control all products.
* In case of operating with more than 2 sets using set ID as '0' at the same
time, it should not be checked the ack message.
Because all sets will send the ack message, so it's impossible the check the
whole ack messages.
* [DATA]: To transmit command data.
* [Cr]: Carriage Return
ASCII code ‘0x0D’
Transmission / Receiving Protocol