I've writte about connecting data and voice channels in customer interaction call centers a while ago. The www.boooming.com website shows an excellent example how this can be achieved: generate a session-ID in the data application (e.g. a corporate website or customer portal), and then let the customer dial a phone number that contains this session-ID - voila! The corporate ACD system can the detect the session ID, and automatically connect the phone channel and the data channel.
Sales Example: customer tries to configure a complex product (e.g. software product or a car) using the online configurator of the vendor. At some point, the customer has a question and needs support. The website displays a phone number that contains a session ID, e.g. 0800-1234-5678, where 5678 is the session ID. The ACD system routes the call to a sales agent, and the session ID is handed over to the sales agent's CRM system which automatically displays the current product configuration that has been selected by the customer.
Customer Service / Remote Support Example: customer needs help with a certain problem, visits the vendor website and requests remote support. The remote support application is launched from the website. The website also displays a phone number containing a session-ID. The customer calls this phone number. The call is routed by the ACD system to a customer service agent. The agent has a software on his system that connects the session-ID from the phone call to the session-ID of the remote support application, i.e. he automatically sees the screen desktop of the calling customer.