There is a reason YOU MIGHT NOT WANT THIS: it has recently disconnected very briefly a few times in the middle of handset-based calls, usually reconnecting immediately, so some patience/experimentation may be involved in getting handset calls to work perfectly, but that's not why you should want this anyway. I have two theories: one is that the power supply is failing — this would be an easy fix for a few pounds off eBay/Amazon; the other theory is that there's something wrong with the handset cable or connectors. I haven't tried exploring either because this is now surplus to requirements: its strong point has always been hands-free calls, and I'm not doing as many of those as I used to.
A Polycom SoundPoint Pro conference 'phone. Polycom are well-known for their excellent and exorbitantly expensive conference 'phones; this one is an old home office one with (I think — never used it!) dual line capability. I can confirm that its hands-free is excellent. It's an old model and never recognised UK caller ID, but otherwise (beyond the above caveat) was my main 'phone until a recent domestic reorganisation.