You would connect it with the rs232 interface and be sure it's all hooked up and everything works. Then send an email to firstname.lastname@example.org
with as much information as you have about the system, including the makes/models and web pages. We will assign someone (we're actually backed up at the moment, so be patient) and they contact you. They will review the protocol and write a basic driver. Then they'll ask you to turn on remote assistance so they can test that it sends/receives the commands correctly, and lastly they'll ask you to visually confirm that it's working.
Normally drivers like that take a day or two depending on the complexity of the system--we only need your help at the end for the visual confirmation, and in the beginning to be sure we understand you hooked it all up.