Are those the handsets that came with or were spec'd for those consoles? The reason I ask is because I know in concept but am lacking in technical details, that there are several different types of handsets. I know the handset that came with my Interalia units is different than a standard handset for a phone - I believe they are carbon handsets but that's the part I'm not sure of. The other type that I think are used in phones and stuff I believe is dynamic, but there are also handsets that have volume control circuitry in them, etc now depending on what phone they came with, some are adapted for hearing aids, etc, so you usually cannot just pick one and install it - like if the originals got misplaced or something.