SamyGO

Ahh - I didn't realize there were two serial modes. (Although I suppose I did read some mutterings about serial control working without any mod in the service menu.) Good info.

Shoot - yeah - the ultimate goal was power-on. Prior to this, I was experimenting with Wake-On, etc, before finding this forum. The samsung guys really don't seem to care so much about external automation. Maybe my next step is one of the IR projects I've seen on this site.

Thanks again for the help, if nothing else, it's been fun.

While I have your attention - you don't have any guesses what the story would be with a Samsung HP-S4253 plasma panel? I believe it's a 2007 model. It has a similar port called "SERVICE 2" - is this likely 3.3v ttl? Able to be powered on?

While I have your attention - you don't have any guesses what the story would be with a Samsung HP-S4253 plasma panel? I believe it's a 2007 model. It has a similar port called "SERVICE 2" - is this likely 3.3v ttl?

Nope . If it's named "Ex-Link" - you should expect regular +-12V RS232 (just a "rule of thumb", I wouldn't be surprised if there are some exceptions).
If it's labeled otherwise ("Service" etc.), all bets are off - could be pretty much anything, TTL level (3.3V or 5V) RS232, regular +/-12V RS232, or something entirely else. Usually, it tends to be 3.3V (or 5V) RS232 in 2008+/A-series models and up.

For HP-S4253, there is service manual available with detailed schematic diagrams (http://elektrotanya.com/samsung_hps4253 ... nload.html). According to the page #70 ("ANYNET & SERVICE I/F", utilizing MAX3232 voltage level converter) there are two separate, external, 3.5mm (?) regular +-12V serial ports on this set. No indication if any of those 2 ports may support Ex-Link protocol or not (I guess not).

Able to be powered on?

I dunno.. one port (called ANYNET) seems to be some kind of predecessor for HDMI CEC (Anynet+) I/F; perhaps it does support power-on? But not likely; looks like it goes (more or less) directly to the S5H2111 SoC, which is probably not active at all while TV is in standby mode.

I think this TV set can also be powered up by PC/VGA port - but it would not be very convenient solution . Or, if you are willing to open it up and solder some wires, you can probably hijack KEY1/KEY2 (CN405 connector); shorting KEY1 to GND usually does the trick (at least in some A,B-Series models models I'm familiar with; YMMV).