Learn how to enable touch tones on the LG Optimus L9.
Turn on / off touch tones (DTMF)
Your phone uses touch tones (DTMF) but you cannot turn the feature off.
Your device can send a number to the network as dual tone multi-frequency (DTMF) tones. DTMF tones are used to communicate with automated systems that require you to type a number such as a code, password, or credit card number. Your phone uses DTMF tones but you cannot turn off or change them.