Hi, Im back on the video switcher project again. We have a TV which you can only turn on by pressing one of the chanel buttons. The power button will only turn it off. That means that for SCART connectors you have to press a chanel then hit the AV button. Im hoping to do away with the TV remote completely since our Sky remote (Satellite TV) has the functionality to control our TV too but it doesnt have the AV button on it. Our Sky box is capable of changing the TV to AV using the SCART lead though.

What i would like to do is have the SCART output from this video switcher box send the same signal to tell the TV to switch to AV mode even if you put it on one of the normal RF chanels. We dont use RF now so thats not a prob. Ive been reading a Wikipedia article about it and near the bottom it appears that i need to output 12V to pin 8. Is that correct or is pin 8 just for the type of input?

One thing that article doesnt seem to mention is when to send the signal. Im under the impression that you must send the 12V signal as long as you want the TV to remain on the AV input and if you turn it off then i guess the TV will reset itself back to the normal chanel. When our TV turns on it doesnt change to the AV chanel if the signal is already being sent (i dont think).

Does the signal have to be a frequency or would a constant voltage do? I want to output this from a PIC chip (through transistor or relay etc). So could i just turn it on or do i need PWM?

Can someone confirm the correct pin and voltage before i go testing please. I know all TVs are different so ill have to experiment a little to get everything right for my TV