LG M4720C Owner's Manual page 60

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 : 01H to 63H. 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