Passing Caller ID through non-CID aware PBX?

[prc1 <prc1@xxxxxxxxx>]

I have an old NuTone PTX-1200 home PBX (2x12) that has worked well for
years.  Unfortunately, it was designed before Caller ID (and other
popular new phone company features) and it will not pass the signal.

Now, as I understand it, CID sends the info on a data burst before the
phone rings for the first time.  My idea is this:  to build a device
that will monitor the main phone line, sense the CID data burst and
will "inject" it on the line(s) to the phone(s) without going off-hook
and preventing the PBX from handling the call.  Each phone extension
line (which normally is connected just to a card inside the PTX-1200)
would also be connected to this device.

Does this sound feasible?  Has anyone heard of the existence of a
device like this?
** To respond, remove the crap from my addy...  **