My next task was to find out why it wasn't working for the CD-in input. I has a good clue to the problem from information on the ir-audio page on the LIRC site. Andrew Zabolotny suggests connecting a diode across the signal and ground pins to shunt any voltage above 0.6v to ground. So with this in mind I went looking for the data sheet for the codec that is present on the Gigabyte motherboard, which is the ALC889A. I managed to find a data sheet for the ALC833, which is a pin for pin match. After having a quick look through I came across this;
As you can see, it specifies a maximum input voltage of 1.6Vrms on the CD-in channels, but the Line-in doesn't, which perhaps explains the reason why it worked on the Line-in input.
Hopefully over the weekend (free time allowing) I can come up with a revised circuit that will limit the signal output from the TSOP1736 to 1.6v ready for part 2 of this HOWTO
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Thanks for the circuit. What I wanted to know is whether this headset jack output style will work when plugging it into the remote control port of my TV Tuner. It is a Winfast TV2000 standard.
Brendan
I guess it all depends on the circuitry inside the Winfast TV2000 whether you could use the TSOP1736 as the source. I am almost certain you will not be able to receive data from the the IR port on the card using audio alsa though as it would not present it self to the system as a sound card. But that shouldn't matter since the Winfast TV2000 uses the BT878 chip, and it has a GPIO register which can be read which will have the scan codes from the IR port. You can use the LIRC 'lirc_gpio' driver to do this.