Your goal is worthy... to autodial from a contact database on your computer... but your approach is probably too wishful.
One method is to have a computer data modem on the same extension or OBi phone port as your desk phone. Then have a contact database that supports autodialing a contact phone number. The user double clicks on the number, the contact program uses the modem to dial the number, and then the user picks up the desk phone on the same line to take over the call. The user may have to dismiss the modem so that it is no longer a party to the call.
I use this method with an old TAPI-enabled contact database program. My OBi202 phone port1 feeds lines L1+L2 to my 2-line house tel wiring, and phone port2 daisy chains L2 through my PC data modem to my desk phone. My PC dials the call and my desk phone takes it over... all on the same extension, line L2.
There may be more elegant solutions, but you will have to discover and understand and implement any such solution according to its design, starting with the ability of the contact database to initiate a call and the ability of the OBi to join your desk phone with that call.
OE