CRM CTI Parameters

Hi Experts,

I am working for CTI Project and I am struggling  to make Ready/Not Ready Active,

For that can any one tell me What are basic requirements for CRM System from CTI Vendor and what parameters in XSTL file  we use to get BP Information based on phone no, if possible can any one explain me the complete process done between CRM and CTI Systems.

Regards,

Krishna.