I noticed today that my Sony 60" XBR has a Control S jack on the back. I have an MX-900, and I recently picked up an MRF-350 to go along with it. I was planning on using an IR emitter to control the TV, but I started wondering if there is any way to use the Control S jack instead. Can the MRF-350 be hooked directly up to the Control S jack? If not, does any company make a device which will convert the commands coming from the MRF-350 into something that the Sony will understand?

The control S can be used but you need to remove the carrier signal from the IR signals, This is easily accomplished in Crestron, AMX, RTI. Im not sure how its done on the URC line of remotes, But it will be a cleaner look if you dont have to stick an emitter on the front of the TV

Might have to have a pronto code set for the TV then edit it in pronto to remove the carrier, or I might have a stripped carrier set in a Hex format for the basics..power and inputs if you want to send me an email so I can send them your way

Rather than editing the files to produce the unmodulated version. Why not do it with hardware! I believe there is a fairly large difference in frequency content between the code and the carrier frequency. Because of this, the task could likely be done with a single pole filter, consisting of a simple RC circuit.

For info: [Link: en.wikipedia.org]

I'm not sure of the frequencies involved off the top of my head, so feel free to send me some info, and I'll help you pick some components. It should be cheap and easy to build.

I would start by choosing the cutoff frequency two decades below the carrier frequency. This would attenuate the carrier by 40dB. (Since an RC filter is 20dB per decade.) For example, if the carrier is 800KHz: Two decades below would be arrived at by dividing by 100. This results in us choosing a corner frequency of 8KHz.

The series resistance poses some questions. We need to know what the input inpedance is on the Control S jack. Anybody know? If it is fairly high, then our choice of R can also be fairly high, allowing us to use relatively small values for C. And smaller values for C are less expensive, easier to find, and physically smaller.

For example, if the input impedance of the Control S jack is 1Kohms (1000 ohms), we would want the R, of the RC filter to be about 1/4 of that or less. If we chose the R to be 1/4th, then the signal coming in will be attenuated by only 20% or 1/5th. This is calculated by:

attenuation in % = Series R / ( Series R + Control S input impedance )

Last we would choose C using a form of the Fc equation from the Wikipedia reference. Specifically: C = 1/(2*Pi*R*Fc), where Fc is the corner frequency we chose in the first step, and R is the series R we chose as about 1/4 of the Control S jack input impedance.

Anyone who knows the input impedance of the Control S jack or can measure one, and the modulation frequency, let me know the info, and I'll go through a couple quick calculations to pick a couple components that should be inexpensive, easily available (although the easiest place to get them may be .... you guessed: Radio Shack), and simple to assemble.

Call Xantech. For Sony Products you need a 794-50 . Its a Universal Interface Module.

[Link: xantech.com]

Well, I got off by Butt and googled Control S and found a bit of info.

The signal levels are plain ole TTL 0 to 5V levels. You only need to output below 0.8V for a zero, and above 2V for a logic one. (I'm assuming standard TTL logic levels, the docs I found didn't elaborate.)

This means dropping a volt using the series R I describe above should not be a problem.

The carrier freq used by Control S is 40KHz. This is a fairly low frequency.

The frequency of the data is logic lows of as short as 0.6ms. This relates to a frequency of about 1667Hz, or about 1.6KHz.

Because these are fairly close in frequency, I would suggest trying a single decade of attenuation, and setting the corner frequency of the filter at about 4KHz. 20dB of attenuation is still a lot, and definitely gets the carrier well below the level of a logic zero.

The good news is everything I read said both the inputs and outputs are TTL, and since the input of a TTL gate is a very high impedance (greater than 10Kohms) picking a resistor should be easy.

So, finding a ceramic 0.1uF capacitor is usually quite easy, so we'll start with that.

The resistor we need for a corner freq of 4KHz is then given by:

R = 1/(2*Pi*Fc*C)=1/(2*Pi*4000*0.1e-6)=398ohms.

Since 390 ohms is a standard value, that seems like a good choice.

So, build a filter as shown in the wikipedia referance. Take care that the side of the resistor without the cap is attached to the circuit that produces the waveform with carrier, and the side with the cap attaches to the Control S jack.

Use a 390 ohm resistor. You will find a 1/4watt axial lead resistor to be easy to solder to, and readily available at any place that carries electronic components. It will not be real picky about tolerance, either 5% or 1% tolerance resistors will work fine.

Use a 0.1uF capacitor. It should be ceramic. Try to get an accurate capacitor. A cap labeled 10% NPO would be good. Better tolerance would be better, but we're not dealin with Rocket Science here!

If you try this, I'd like to hear how this turns out... don't worry, I won't ask for much in terms of royalties for this circuit :-)

Good luck, happy Soldering!

Oops... double post.

heads up plugging in to control s sometime disables the ir reciever in the front of the tv. so you can use both