IVR on dedicated webserver

I need guidance from someone with? experience in IVR? to help me? setting up an IVR system on a dedicated webserver in a datacenter in London. This is a typical loop: Hello caller, please input the job number. Php code will listen, look up the database, prepare the text then play text to speech to caller. The main difference between what this project aims to achieve and a ready made IVR such as voipfone? is the use of php to create the voice files and? the IVR script, giving the system the ability to access an external URL for? answer to? the caller's questions. My webserver runs ubuntu linux with MySQL, php and exim4.