Secure DTMF Cancellation
For security and privacy reasons, you can remove all Dual-Tone Multi-Frequency (DTMF) information that the
Oracle® Enterprise Session Border Controller (E-SBC) processes by enabling
secure-dtmf-cancellation within the codec-policy. For example, you might want to cancel all DTMF tones when processing credit card numbers, debit card numbers, PIN numbers, and other DTMF-based passwords that you want to remove from the media stream. When an incoming call requires DTMF cancellation, the
E-SBC uses the built-in detection and cancellation mechanism to completely remove all sixteen DTMF tones on ingress making the tones undetectable on egress. (0-9, *, #, A,B,C,D)
In contrast to standard DTMF cancellation, which leaves some residual signal energy at the beginning and ending of each DTMF digit,
secure-dtmf-cancellation removes all signal energy from the media stream by adding an extra 10μs to the leading and trailing edges of the DTMF tones. The result is silence for the entire duration of each DTMF digit because the system mutes all audio when you suppress DTMF tones with
secure-dtmf-cancellation.
- PCMU
- PCMA
- G.726-32 (and higher)
- G.722
Secure DTMF cancellation supports hardware transcoding only. You must own the transcoding license and you need transcoding resources, such as a Digital Signal Processor (DSP). In addition to enabling
secure-dtmf-cancellation in the codec policy, you must enable
dtmf-in-audio in the codec policy. You can enable
secure-dtmf-cancellation and
dtmf-in-audio in the ACLI and the Web GUI.
Note:
An endpoint configured as secure at the session startup stays in the secure mode throughout the call because you cannot re-configure the DTMF cancellation mode during the call.
