To store DTMF tones
For information on how to send DTMF tones, see ”Multiple calls” on page 62,
or ”To send DTMF tones” on page 152.
If you need both a voice and a DTMF phone number for the contact, store the
DTMF sequence in the Tel field, in which case the phone number and the DTMF
sequence must be separated by one of the special characters in table 1. Or add
a DTMF field to the contact card with the Add field command.