ADNOS is accessed via an API. Multiple interfaces are supported, including XML-RPC, JSON and serialized php.
Usually ADNOS customers do not want the end user to know the true destination of a phone call, so API calls are made from server to server, however the system is completely platform independent, connections can be made from your server, a browser on a PC or from a smart phone.
The most common ADNOS request is to overlay a number. When you make an overlay request, the system will check to see if an existing overlay meets your requirements, then return that number or create a new one. The other functions are statistical in nature, either checking what calls have gone through or setting up mechanisms to allow more detailed reporting suitable for your needs.
There is also a web interface available at stats.adnos.co.uk from which you can view call stats and manage your advertisers.