Just to add a little twist to all the info already in thread.
Mine is a MK1 acording to the picture from the first post, makes sense as I bought it when it first came out.
At first the base was built in to the charger - one phone to one base. But it was later upgraded (free of charge) to a system phone, and I now use it along side my BeoCom 6000's. And the charger/base is now just a charger.
/MikaelB