Customer moved into new suite back in April 2018.
There was an NEC DX7NA / DS2000 already on the wall.
I ordered two more 22 BTN phones to supplement the two they already had.
Now customer calls 6.5 months later to complain they do not get caller ID on their phones.
They pay for the service through their carrier.
Does this phone system have the capability?
Does it need special card?
Special programming.
Call log button? etc. etc. ??

Any thoughts, idea or suggestions would be greatly appreciated.

Thank you very much in advance for your time and effort spent on my behalf

That is an old NEC DS2000. In order to get caller ID you'll need a caller ID daughter board for the trunk card as well as proper programming for the caller ID to display on the phones. The first thing to check is if you have one of these attached to the trunk card

NEC DS2000 DX2NA-8CIDU-A1 8-Port Caller ID Daughter Board (80013)

If you have that then you'll want to follow the caller ID programing procedures from the software manaul.

Thank you nortelvoip.
I just noticed in my 6 month old notes that I do have written down DS2000

If the trunk card part number ends with a B (example 80010B) the caller ID is built into the trunk card, if no B it requires a daughter board.
If the system defaulted caller ID will need to be enabled.
There is a Sony battery on the CPU card, its replaceable and I bet has never been.