Headset Prior (Yealink T21P)

[jolouis]

Underlying problem is you are using T21's with a physical handset lifter. The phone doesn't understand that you're lifting the handset to answer the headset... the normal flow with a headset is to press one of the buttons on the phone to answer the call VS lifting the handset itself.

I'm not aware of any options that you can use to disable that, maybe somebody from Yealink can chime in. A more ideal solution would be to use EHS, but since the T21 is too basic to support that unless you want to replace the phones that's not really an option...