LG M1950D Owner's Manual page 76

76
EXTERNAL CONTROL DEVICE SETUP
23. Channel Tuning (Command: m a)
To tune channel to following physical/major/minor number.
Transmission
[m][a][ ][Set ID][ ][Data00][ ][Data01] [ ][Data02][ ] [Data03][ ][Data04][ ][Data05][Cr]
Digital channels have a Physical, Major, and Minor channel number. The Physical number is the actual digital channel
number, the Major is the number that the channel should be mapped to, and the Minor is the subchannel.
Since the ATSC tuner automatically maps the channel to the Major number, the Physical number is not required
when sending a command.
Data 00: Physical Channel Number
NTSC air: 02 to 45, NTSC cable: 01, 0E to 7D
ATSC air: 01 to 45, ATSC cable: 01 to 87
Data 01 & 02: Major Channel Number
Data 01: High byte
Data 02: Low byte
Two bytes are available for the Major and Minor, normally only the second byte is used.
Data 03 & 04: Minor Channel Number
Not needed for NTSC.
Data05 :
7 Main/Sub Picture 6 Two/One
0 Main 0 Two
1 Sub 1 One
The table above lists the binary code that must be converted to hexadecimal before sending. For example, the binary
code to tune the sub source to an NTSC cable channel is "1000 0001", which translates to "81" in hex.
* 7th bit: for which source do you want to change the channel.
* 6th bit: use a two part or one part channel. Most cases just use 0 since it's ignored when using NTSC.
* 5th bit: use 0 with NTSC since it can only use the physical channel number. Normally use 1 for ATSC since most
times it doesn't matter what the physical number is
* 4th bit: set to 0.
* 3-0 bits: choose signal type.
* Tune Command Examples:
1. Tune to the analog (NTSC) cable channel 35.
Data 00 = Physical of 35 = 23
Data 01 & 02 = No Major = 00 00
Data 03 & 04 = No Minor = 00 00
Data 05 = 0000 0001 in binary = 01
Total = ma 00 23 00 00 00 00 01
2. Tune to the digital (ATSC) local channel 30-3.
Data 00 = Don't know Physical = 00
Data 01 & 02 = Major is 30 = 00 1E
Data 03 & 04 = Minor is 3 = 00 03
Data 05 = 0010 0010 in binary = 22
Total = ma 00 00 00 1E 00 03 22
Acknowledgement
[a][ ][Set ID][ ][OK][Data00] [Data01] [Data02][Data03][Data04][x][a][ ][Set ID][ ][NG][Data00][x]
5 Using Physical
Part Channe Channel
0 Use
1 No Use
4
3 2 1
Reserved
x 0 0 0
x 0 0 0
x 0 0 1
x 0 0 1
x 0 1 0
x 0 1 0
x 0 1 1
x 0 1 1
x x x x
x 1 1 1
0 Step
0 NTSC Air
1 NTSC Cable
0 ATSC Air
1 ATSC Cable_std
0 ATSC Cable_hrc
1 ATSC Cable_irc
0 ATSC cable_auto
1 Reserved
x ...
1 Reserved