A telecommunications system including a digital cellular network, and a call center having a central converter connected to the network, and operable to convert an incoming signal from a first format to a second format. The call center has a TTY/TDD device operable to read the signal in the second format...http://www.google.com/patents/US20020085703?utm_source=gb-gplus-sharePatent US20020085703 - Facility and method for cellular data communication between hearing impaired users and emergency service centers
