LG M4210LC Owner's Manual page 42

RS-232C
Transmission / Receiving Protocol
Transmission
[Command1][Command2][ ][Set ID][ ][Data][Cr]
* [Command 1]: First command. (k, j, m, d, f, x)
* [Command 2]: Second command.(a to u)
* [Set ID]: Set up the Set ID number of product.
range : 01Hto63H. 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.
Transmit 'FF' data to read status of command.
* [Cr]: Carriage Return
ASCII code '0 x 0 D'
* [ ]: ASCII code Space (0 x 20)'
OK Acknowledgement
[Command2][ ][Set ID][ ][OK][Data][x]
* 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
[Command2][ ][Set ID][ ][NG][Data][x]
* If there is error, it returns NG
Controlling the Multiple Product
A4