US patent application 2220110228919 (USPTO link) seems to be trying to patent an on/off switch for DTMF audio on telephone networks.
The key claims are these (effectively the first three):
A telephone call processor for processing telephone calls comprising voice signals and data signals, the call processor comprising a first telephone interface and a second telephone interface, the call processor being operable in a first mode and in a second mode, wherein:
- in the first mode, the call processor is adapted to receive voice signals and data signals at the first telephone interface and to transmit voice signals and data signals to the second telephone interface;
- and in the second mode, the call processor is adapted to receive voice signals and data signals at the first telephone interface, to block data signals from being transmitted to the second telephone interface and optionally to transmit voice signals to the second telephone interface.
The call processor of claim 1, wherein the data signals comprise at least one of audio tones and DTMF (dial-tone multi-frequency) audio tones.
The call processor of claim 1 further adapted to switch between first and second modes in response to receiving a mode-switching data signal at the first or at the second telephone interface.
The application itself describes how this approach can restrict credit card information being sent by a customer from reaching the ears of the call center agent, or the call recording systems operating in the call center. It therefore stops call center staff from stealing card data.
The concept of stopping call center staff from accessing sensitive data transmitted by DTMF is not new. One example is Van Volkenburgh's application from 2003 Device and method for concealing customer information from a customer service representative
The concept of blocking DTMF tones is not new either, as shown by Didier Filhol's application of 1998 Telephone dialling modification accessory, e.g. to ensure use of specific service provider, has off-hook detector actuating unit to filter out DTMF signals and generate replacement signals as necessary
However, to my layman's mind, don't the claims in the 2220110228919 application above mean "sometimes DTMF tones are allowed to come through to the call center agent, and sometimes they are switched off"? In other words, it's an on/off switch.
The current application states a UK reference date of May 9, 2008.
Question: Does anybody have any prior art for this?