I've seen a few audio visual equipments that can be controlled with both wired (3.5mm stereo jack) and wireless (infrared). On the equipments, there are IR receiver port and also a port that resemble audio in port used for wired remote control.

On the remote control side, it also has both IR transmitter and 3.5mm port.

I have no problem deciphering and emulating the infrared code that the infrared remote generates but I am wondering how does the 3.5mm jack control works. Is there any standard or protocol for this or does each manufacturer creates their own?

How do I capture the stuff sent from 3.5mm port of the remote control to the equients? Any idea?

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    \$\begingroup\$ I'd make a wild guess that the wired communication protocol is the same as the IR one - then the manufacturer wouldn't have to deal with two communication protocols. \$\endgroup\$ – Peter Bennett Feb 1 '15 at 4:27
  • \$\begingroup\$ What are the make(s) and model(s) of the audio equipment in question? Sony used to (may still) use the LANC protocol for device control, which sometimes used a 2.5mm stereo jack. \$\endgroup\$ – markt Feb 1 '15 at 9:08
  • \$\begingroup\$ I think you are right, Peter!I saw one post that confirm your guess : wiredremotecontrol.blogspot.sg/2005/10/… \$\endgroup\$ – scott Feb 2 '15 at 0:59
  • \$\begingroup\$ Hi Markt, it's an Onkyo TX-NR807. \$\endgroup\$ – scott Feb 2 '15 at 1:01

For capturing the signal you need an oscilloscope or logic analyzer. The easiest thing that comes to mind is a Bus Pirate used as a logic analyzer. They are pretty cheap and useful for lots of things.

  • \$\begingroup\$ Thanks for the suggestion, Austin! Will look into it although I have never used one before. \$\endgroup\$ – scott Feb 2 '15 at 1:02

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