I upgraded my system from Fedora 20 to 23, and in the process from asterisk
11.3 to 13.1 . After some fiddling (recompiling Dahdi, installing extra packages such as asterisk-dahdi and asterisk-sip), everything mostly works, except the buttons on the Dahdi phones. Calls can be initiated from the SIP
phones, but on the Dahdi phones, the first numeric button press generates a fast busy. Inbound calls to the Dahdi phones work just fine.

Any ideas on where I should look to fix this?

I am using a Digium TDM410 PCI card.

Thanks,
–Greg