Which of the following are SIP methods that can be used to pass DTMF tones? (Choose 3 answers)

Which of the following are SIP methods that can be used to pass DTMF tones? (Choose 3 answers)
A . In-band method by encoding DTMF tone as regular RTP packets
B . In-band method by encoding DTMF tone as in specific RTP packets (RFC 2833)
C . Out-of-band method by encoding DTMF tone in SIP message (UPDATE method)
D . Out-of-band method by encoding DTMF tone in SIP message (MESSAGE method)
E . Out-of-band method by encoding DTMF tone in SIP message (INFO method)

View Answer

Answer: B,D,E

Explanation:

Reference: http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/voice/sip/configuration/12­4t/sip-12-4t-book/voi-sip-dtmf.html#GUID-0E228A53-4405-4730-8D54-B37979E69A8B