DECT Wireless Headsets

I'm hoping some of you guys might help me with this surprising problem. I picked up a used Sennheiser DW Office Dect wireless headset:

http://en-de.sennheiser.com/wireless-headset-office-hands-free-dect-dw

I've tried the consumer dect headsets from Vtech and AT&T and they totally suck. This Sennheiser has good reviews, so I thought I'd try it. However, at home I only have a cordless phone and it seems the Sennheiser (as well as the other office systems like Plantronics) require a corded phone so it can plug into the handset receptacle. It will also work with handset lifters, headset connectors and receptacles, even USB (on Windows), but the damn thing won't plug straight into a friggin wall jack, like every other phone on earth!

There have been a few emails back and forth with Sennheiser and they confirm this, unapologetically...

So, I'm trying to figure out my options. I can pick up a corded phone and plug into the handset port. But I think I'd need an adapter cable for that because the phone jack receptacle in the Sennheiser is one of those bigger RJ45 or something like that, I don't think they're the same size. And once I got that working, I'd have to physically lift the handset to use the headset, unless I spend $$$ for a handset lifter or the more sophisticated electronic handset lifter.

Why is it so hard and expensive to make a high quality wireless headset for the phone when good cordless phones are a hundred bucks or less? Maybe I'm trying to make an apple into an orange here, but... Any ideas?

HAPPY HOLIDAYS, BTW

 

no thoughts?