Chapter 7
DTMF Interworking
At some point, you have heard a prerecorded prompt requesting some information, perhaps a credit card number or an employee number. After a couple of presses on the keypad, you magically get the information you were looking for or are connected to a human agent. The underlying framework that enables this seamless transfer of information is known as dual-tone multifrequency (DTMF).
With the advent of voice over IP (VoIP), reliable transmission of keypad button presses end to end became somewhat of a problem, as audio codecs were not optimized for carrying DTMF tones without bringing in a degree of distortion. There was need to engineer a new way of reliably transmitting DTMF. This solution aimed to factor in all the ...
Get Understanding Session Border Controllers: Comprehensive Guide to Designing, Deploying, Troubleshooting, and Maintaining Cisco Unified Border Element (CUBE) Solutions now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.
