Received service cards
A DTMF service provider may send DTMF se-
quences to its subscribers in the form of a service
card that can be stored as DTMF contact cards.
For more information on Dual Tone Multi Fre-
quency (DTMF) tones, see chapter 13 "Phone in-
terface: Sending DTMF tones" on page 13-3.