The RF switchbox for the Magnavox equipment is unique and the RF cable does not terminate with a RCA plug .. So I opened up my O2 and easily replaced the RF cable with an Atari one ..
The voice chip inside the Odyssey Voice Module is from the same family of voice chips as those inside the Intellivoice and the new VecVoice module. They are called the General Instruments SPO256 family of chips.
I like Killer Bees .. and I have the Voice Module for it. Smithereens is a great game! It needs to be ported to the 2600!
I have not seen too many other O2 games that I like .. and I cannot get into board based video games.
If your O2 features unpluggable controllers, you can connect an Atari stick to it via a small adapter. I make these adapters for $6 each. contact me via private email to get one.
The O2 power supply gives 9v AC out and uses an 1/8" phono plug. Easy to find a replacement at any thrift store.
Also I recently picked up the O2 programming manual at a thrift .. The cart was nowhere to be found!

That is a good read though and a real intro to programming! (unlike the Basic Programming for the 2600).
Now if the powerful Bally Astrocade had been built with the O2 keyboard .. wow! It would have dominated the video game industry!
Rob Mitchell, Atlanta, GA