DTMF stands for Dual-Tone Multi-Frequency, and it is how phone companies know what number is pressed when a customer touches the numbers on the telephone keypad.

When a telephone keypad is used to input payment data such as a credit card, those tones can be intercepted by hackers to collect credit card information, unless DTMF masking is used.

DTMF masking involves intercepting substituting (masking) the unique audible tones with flat tones so that people who hear the DTMF data cannot decipher the numbers.  The masking software usually sits between the caller and the call centre (or contact centre) system and converts the DTMF tones to flat tones.

IPSI uses DTMF masking for the AgentSecure^® service.