Gimitel,
You will need to be a little more specific on what it is they want exactly.
Are they looking to have a KSU instead of PBX style system? The 5000 can do either one, but it sounds like it is currently setup to be a PBX since it has Call Keys.
Are they just wanting to see the lines and whether or not they are busy and not use them to make calls, but to continue to use the Call Keys?
What is the reasoning behind this whole question from your customer?
Thanks,
TE