ClaritySR100 Super Loud Phone Ringer

Q: can I use a phone jack splitter to add this to a single phone jack?

Yes, you can. But you dont really need a splitter because it has an extra jack on it to plug your phone into. So... there are 3 options: 1) plug your phone into the ringer 2) use a splitter, or 3) plug it into a totally different jack in the house. All 3 of those will work.

Q: Will it ring if the phone is plugged into a different jack?

As long as you have it plugged into a jack.

Q: will it workwith a wireless phone?

as long as the phone uses a modular telephone cord it will work, whether it is corded or wireless will not matter, you will need to connect it at the base