I use it a lot on phones other than my cell or office phone (I use a Bluetooth connection for those).
I like the duophone thing. You decide which ear will be the main one, and your pro will set them for that. Then when you use a phone, and put the phone up to your main ear, it picks up the conversation and sends it to the other ear. I have found it to work very well. It gives you the phone conversation loud and clear in both ears.
It doesn’t matter what kind of phone you use and there is no extra equipment.