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New Member

DMP with RS-232 function

Dear All,

Have anyone try to use DMP control LCD TV via RS-232? My LCD is LG LCD TV 42LH20R.

Communication Parameters
- Baud rate : 9600 bps (UART)
- Data length : 8 bits
- Parity : None
- Stop bit : 1 bit
- Communication code : ASCII code

I can turn on / off via my PC serial port with command

     Turn On = "ka0101"

     Turn Off = "ka0100"

But I don't know how to config in DMP.

Can anyone help me?

Best Regards,

Sukitti L.

New Member

Re: DMP with RS-232 function

Try this.

The short answer is that you will need to create a "System Task" on the DMM under Advanced Tasks to send the specific RS-232 command to the DMP to control the display..

Displays are controled by Hex codes. Look at your manaufacturers's display model published hex codes for command and control codes for the display in question.

Here is a website that has the Ascii to hex conversion info you will need. Others exist.

Below is a sample set of System Tasks control applications settings for the DMM with a Sharp LCD as a sample.

Sharp - RS232.Control

To use the RS232 commands on the DMP the serial port must be set to ON and be pointed at the /dev/ttyS1 device. To check this create a System Task in the DMM to check your settings using number 1 below.If your serial port is anything other than /dev/ttyS1 use number one to set it correctly.

1 Create a system task under application

name it "RS232 ON"

request type = "set"
request= init.startService_rs232=yes&rs232.device=/dev/ttyS1&

2 Create system task "RS232 OFF"
request type = "set"
request = init.startService_rs232=no&rs232.device=/dev/ttyS1&

3. Create system task "TV On" (((ascii =powr1_ _ _ + cr)))
request type = "set"
request = rs232.tx_hex=504F5752012020200D

4. Create system task "TV OFF" (((ascii =powr0_ _ _ +cr)))
request type "set"
request = rs232.tx_hex=504F575200202020OD

I hope this helps.


C.O. Little

New Member

Re: DMP with RS-232 function

Hello charleslittle

Greetings from Slovakia.

Thank you very much for the link to asci table. I was just looking for it. You were very helpful.

I was just about to control LG screen as well. The funny thing is that the Cisco Doc I have, does not say anything about the hexa conversion. It says 'send the hexa codes and you will get the same hexa codes from RS232'

I found that out over ehtereal.. sniffing functional Cisco Screen control .. that DMP was sent different code than output.


You say I need to turn on RS232 control. So it is OFF by default and by turning it on ( DMP will reboot after that) ... it will stay turned on forever?

Hey sukitti.l

To turn on LG you need to enter space between the parameters.

Turn ON is  'ka 01 01'    well or 'ka 1 1'  is also working (in case you ID is set to 1) . Otherwise you get korean NG instead of OK.

Turn off is 'ka 01 00'    and THAT you need to convet to hexa also with SPACE character 0x20

Switch to HDMI1 'xb 01 90'

That is all I need.

Example ..

task "LG TV OFF" ( ka 1 01 +CR      ...this is what you want DMP to send over rs232 laplink)
request type "set"
request = rs232.tx_hex=6B6120312030310D

This should work on all LG screens .... hopefully..

I tested three so far.

M2794DP, 42LG3000, 42LG2000


Tomas Truchly

ANECT Slovakia

New Member

Re: DMP with RS-232 function

Dear All,

Thank you very much. Now I can using DMM to turn on/off LG LCDTV.

Hi. Tomas Truchly

As I config after we turn on RS-232 service. It will stay on forever even we reboot DMP. So turn on only one time / DMP.

BTW I would like to ask whether. What scenario all of you using DMP?

     1.     Play content from local (Using SD Storage inside)

     2.     Play content from local (Using External Device connect to DMP ex. Thumbdrive, External HDD)

     3.     Play content from web server (Using url get contents then play)

Now I using Option 2 but consider migrate to option 3. Because limitation of Thumbdrive, I need to replace data everydays sometime I got Thumbdrive freeze unable to re-write data.

Thank you for all.


New Member

Re: DMP with RS-232 function

I am trying to setup the same using LG Plasmas from 32"-60" in size.  I have setup all the RS232 commands listed here as well as performed the RS232 enable script, but nothing seems to work.  Are there any recommended troubleshooting techniques to find a solution for this?  These TV's were previously used with RS232 and Digi One SP boxes successfully.


Sukitti, we will be using option #3



After testing with a Digi One SP at the other end of the rs-232 cable (can view the output via a telnet session) I finally found the code that the 4400 would pass thru.  Apparently the the extra code for the "0" for the data field (01 vs 1) was causing issues.  I used rs232.tx_hex=6B61203120310D.  I was then able to get it working for on, off, mute, various preset volumes, and different inputs.  Thanks for all the information in this thread, it was VERY useful.

New Member

Re: DMP with RS-232 function

Yes. That one more zero sends CR. or something like that.

Well. It's easy to see what DMP is sending, you can just connect it to com port of your computer.

It's very easy to control LG monitors now :  ).

Sukitti, Our customer is playing MPEG2 videos from local flash. Every player is behind NAT connected with DSL.