Yes, the older dial phones (700 series and trimphone - okay, so you can mimic one!) have dynamic earpieces, and that's what the induction coil was designed to work with. Pretty much any 'loop disconnect' phone is likely to have a dynamic earpiece.

'Loop Disconnect' is the old dialling system where the dial simply closed and opened the line rapidly to provide the dial signal to the exchange. They play have with domestic installations where people try to mix them with modern digital phones! It used to be possible to 'dial' a number just by tapping the cradle if you knew what you were doing!

Some modern phones are available with an induction loop for hearing aid users, but by no means all. Such a phone will work with your induction device.

If you'd like to use my TBU setup to do it, I'd be happy to oblige - PM me for my email address/phone number. I'm based near Manchester UK... if that's too far away, you can rent one from most PA hire companies, and they are fairly easy to use once you are shown how.

Basically, they split the audio into two channels - earpiece signal and mouthpiece signal, just as a telephone handset would do, but more controllable. That way you reduce the risk of feedback in a 'live' situation.