In band DTMF Digits 1 – 9 from a local SIP phone
In
band DTMF Digits 1 – 9 from a local SIP phone
In
band DTMF digits 1 – 9 from a PSTN POTS phone via SkypeIN
In
band DTMF Digit “1” from a local SIP phone
In
band DTMF digit “1” from a PSTN POTS phone via SkypeIN
Spectrum
Analysis of DTMF Digit “1” from a local SIP phone
(696 hz + 1209 hz)
Spectrum
Analysis of DTMF digit “1” from a PSTN POTS phone via
SkypeIN
(698 hz + 1206 hz)
Table
of Peak Frequencies for SIP and SkypeIN DTMF tones
Scenario:
(SIP ATA)-->(sofia)-->(fs)
(POTS)-->(PSTN)-->(skypeIN)-->(skype_client)-->(skypiax)-->(fs)
Conclusion:
Although the DTMF tones are attenuated there does not appear to be any major filtering or distortion of the DTMF tone when transmitted across the Skype network.