We would like to know which office-wide DECT systems are suitable for
connection to our existing PBX.

An office-wide DECT system is a system with multiple DECT base
stations and multiple handsets, allowing users to use their handset
anywhere in the office, and allowing seamless handover from one base
station to another during a phone conversation.

Many such systems contain PBX functionality, and are therefore not
suitable for operation with a standard PBX. For our purposes, the
handsets should appear to our PBX as standard extensions, individually
controllable from the PBX.

Our PBX is Interaction Center, manufactured by Interactive
Intelligence, see http://www.inin.com for more info. This is a
software system running on a Windows NT server, using (in our case)
Dialogic cards for trunk and station lines. The obvious ways to
connect a bunch of extensions are (a) individually, using POTS or ISDN
BRI connections, or (b) collectively using an ISDN PRI. It is
important that the DECT system appear from the perspective of the PBX
exactly like a bunch of extensions, and that there not be special
protocols needed to control it.

Can you list 4-5 DECT systems available on the market that would
fulfil our requirements?