300-085 · Question #153
Refer to the exhibit. An IP phone user cannot log in to their Cisco Unity Connection voice mailbox with their PIN. Which command will most likely resolve the issue?
The correct answer is A. dtmf-relay rtp-nte. When an IP phone user cannot enter a PIN to access Cisco Unity Connection voicemail, the dial peer is likely missing a correct DTMF relay method, causing touch-tone digits to be lost or distorted over the VoIP network. Configuring rtp-nte ensures PIN digits are transmitted…
Question
Refer to the exhibit. An IP phone user cannot log in to their Cisco Unity Connection voice mailbox with their PIN. Which command will most likely resolve the issue?
Options
- Adtmf-relay rtp-nte
- Bmgcp dtmf-relay CODEC all mode out-of-band
- Cdtmf-relay h245-alphanumeric
- Ddtmf-relay sip-notify
How the community answered
(14 responses)- A57% (8)
- B21% (3)
- C14% (2)
- D7% (1)
Why each option
When an IP phone user cannot enter a PIN to access Cisco Unity Connection voicemail, the dial peer is likely missing a correct DTMF relay method, causing touch-tone digits to be lost or distorted over the VoIP network. Configuring rtp-nte ensures PIN digits are transmitted out-of-band per RFC 2833.
The dtmf-relay rtp-nte command configures the dial peer to transmit DTMF digits as RFC 2833 Named Telephone Events out-of-band, bypassing codec compression that would otherwise corrupt in-band tones. This is the standard and most widely supported method for SIP-based voice calls to Cisco Unity Connection. Without it, PIN digits entered on the IP phone keypad may never reach the voicemail system intact.
The mgcp dtmf-relay command is specific to MGCP-controlled gateways and has no effect on SIP dial peers used in a Cisco IP phone to Unity Connection scenario.
The dtmf-relay h245-alphanumeric method applies to H.323 signaling and is not used in SIP-based call legs connecting to Cisco Unity Connection.
While dtmf-relay sip-notify can carry DTMF via SIP NOTIFY messages, rtp-nte is more universally supported by endpoints and Cisco Unity Connection, making it the more reliable and likely fix.
Concept tested: DTMF relay configuration for VoIP voicemail PIN access
Source: https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/voice/dial_peer/configuration/15-mt/vd-15-mt-book/vd-dtmf.html
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