If your outgoing trunk to the PSTN is a analog trunk, 2 wire plain POTS, you need to find out from your local phone company what is the code to disable caller id.
It should be something like *67 or something like that.
This is the number that the Quintum will dial before any other digits when placing a call to the PSTN.
Then you enter those digits as a prefix to be dialed before the real called digits.
Be aware that you could not always be sure that the caller I.D. is not displayed. There are ways to get the caller I.D. even if you blocked the transmission, an you do not need to be FBI or CIA to do it.