My client needs 23 cameras on his property, 12 of which are to be PTZ.
The system will be a 32 ch pc DVR with PTZ control.
How do I connect all of the PTZ cams to the PC so that I can control each of them ?

You will daisy chain the PTZ controls....what DVR and cameras are you using?

Do not control your PTZ by DVR

get stand alone PTZ controller

just make sure you get the same brand of ptz's as your dvr and controller

The PTZs are from USAG in Florida.
I take it the standalone controller is better ?

the standalone controllers are much easer to quickly use and program and get the full used out of the ptz's. you can control the ptz's by dvr just also have a standalone controller in the mix also.