The "2nd Audio Input" or "Extra A/V Input" modification is the addition of another set of Left/Right audio input connectors. This modification, combined with a software switch via the "palmod_config" utility on the OzTiVo image, effectively splits up the two video input connectors (RCA and S-Video) so you can feed in two totally separate A/V sources. This is an advantage if you have two external input sources - for example: Foxtel pay-TV and also a digital set-top Free To Air (FTA) box for normal TV. The following picture shows how this is achieved:
View of a TiVo with the "2nd Audio Mod"
As can be seen the existing Left/Right inputs are used with the composite video RCA connector and the new set of Left/Right connectors are used with the S-Video connector. If both your external sources are RCA you can purchase an RCA-to-SVideo converter plug from places like Jaycar Electronics.
Does the TiVo then switch between each input automatically?
Yes. The TiVo is smart enough to map each channel from each box, and knows what input to switch to automatically when you select the appropriate channel. This applies to both "channel surfing" and also when setting up programs to record.
Does this allow for the recording of two programs at once, or the ability to watch one input while recording from the other input?
Unfortunately no. TiVo hardware only supports the recording of a total of ONE input
at a time. Even watching live TV is actually being recorded into a
continuous 30-minute buffer so you can pause or rewind "Live TV". The ability to make a Series 1 TiVo record two programs at once cannot be changed at neither software
or hardware level.
You can, however, be recording one program while watching the same one at a different point (the so-called "time shifting" feature) or you can be recording one program while watching another previously recorded program.
What about the IR Blaster? Will it control both STB's I connect to the TiVo?
Yes! Just like with the TiVo knowing which input to select, it will also map the appropriate IR codes for each box.
For those wondering if connecting two boxes will conflict with the TiVo IR Blaster please remember that just like how your normal handheld remote control spits out specific codes for the STB it was designed for and all other boxes (usually) ignore that remote control, so does the way TiVo works. Manufacturers of STB usually design their codes to be unique to that particular box. So therefore the TiVo will, just like your remote control, produce the same type of codes for the STB you program it for and each box will only respond to it's own unique IR codes and not interfere with the other STB.
Can both the "PAL Tuner Mod" and "2nd Audio Input Mod" be done to the same TiVo?
Yes. But you cannot have all three inputs active at once. You can pick, via software, for the internal tuner and one A/V input, or alternatively pick for both A/V inputs and no internal tuner. Not all three at once. Although this is the case for inputs, outputs are a different story. Every output from a TiVo is always functional at the same time, so it is your choice if you decide to use the RCA, S-Video or the UHF RF output from the PAL tuner. Also because all outputs are buffered separately you can use more than one of them at the same time. Handy if you wish to feed the TiVo signal to different places in your home setup.