Multimodal telephone calls

A method implemented on a first computing device for establishing a multimodal telephone call, the method comprising:

• on the first computing device, receiving a first request message from a second computing device to register a data session for the second computing device, the first request message including a first telephone number and a second telephone number;
• on the first computing device, receiving a second request message to register the data session for a third computing device, the second request message including a third telephone number and a fourth telephone number;
• on the first computing device, determining whether the first and second telephone numbers in the first request message match telephone numbers in other received request messages;
• on the first computing device, when it is determined that the telephone numbers from the second computing device and the third computing device match, creating a key for the data session between the second computing device and the third computing device, the key providing a unique identifier for the data session.

A computer-readable storage medium wherein the computer-readable storage medium does not include a transmission signal comprising instructions that, when executed by a client computer, cause the client computer to:

• receive a telephone call from a second computing device;
• send a response to the second computing device that a telephony session is established between the client computer and the second computing device;
• send a first request message to register the client computer for a data session at an online registry service, the first request message to register including a first telephone number associated with the client computer and a second telephone number associated with the second computing device, the first and second telephone numbers being utilized by the online registry service in an attempt to match the first and second telephone numbers with telephone numbers received from other request messages to register, received at the online registry service;
• receive a response message indicating that the client computer is registered at the online registry service, the response message including a key that uniquely identifies the data session;
• and
• initiate a second request message to send data to the second computing device, the second request message including the key.