BT Web21C API - Comments
deprecated
From their site: BT is undergoing a complete transformation. At the heart of this transformation is our �10 billion 21st century network (21CN) initiative. An IP-based, multi-service network, 21CN is the driver for a radical change. As part of this change, we are kicking off a ground-breaking project, code-named Web21C. The Web21C SDK includes APIs for SMS, Voice Call, Conference Call, Presence, and Location.
This API is no longer available, as BT has now invested in 'Ribbit' which doesn't seem to have quite the same functionality :'(