SX Specific DTMF I/O

• Ubicom Application Note 41: "DTMF Detection and Generation". Designed to be compliant with the Scenix SX Modem evaluation board. PDF Source
• DTMF detection. Compliant with the Scenix SX Modem evaluation board with a minor modification to the board; the input filters have to be disabled.

Also:

• SX Specific Telephone I/O
• Plain Old Telephone Service