DTMF not working while using Speakerphone

[cpinero]

I am using Linksys SPA922 phones and the DTMF works fine when using the handset, but does not work when using the speakerphone. Is there a setting that I have to change on the phone to allow this?

 

[archie]

Probably in speakerphone mode your mic catches beep and it interfere with inband DTMF. Try to switch to RFC mode (out of band).