Hello, I'm Joseph, an Austin, Texas based PHP developer for 11 years.
I have not worked with ZOHO's API (worked with their CRM some years ago), nor have I worked with Vicidial, but I've worked with a wide variety of JSON and SOAP (XML) APIs over the years and I've never met an API I couldn't communicate with.
I'd love to chat and get some specifics.
Regards,
Joseph Cardwell