T28P Constant Ring Instead of DialTone

[kruoll]

Hello,

I have a mix of Yealink phones... T22, T26, and T28P. T22 and T26 get a standard dial tone, but all T28P make a ringing noise when picking up the line. All are configured in Elastix 2.0.0-63. I have tried factory reset. The phone operates as normal both inbound and outbound, except for this strange dial tone. Any ideas?

Thanks for your input.