Just finished the install of purple 17571, and got it to work with my pots card a TDM400P. then installed incredible to find out all my config was wiped out. should have RTFM one would say.
but for what is worth all I had to do was this:
Before I installed incredible, I…
ran dahdi_genconf -vF
this will generate the config for freepbx

edit the dahdi-channels.conf I only have 2 fxo ch 1 and 2 and 2 fsx ch 3 and 4 so I commented ( everything and and left just this:
signalling=fxs_ks
callerid=asreceived
group=0
context=from-zaptel
channel => 1

signalling=fxs_ks
callerid=asreceived
group=0
context=from-zaptel
channel => 2

rebooted, created my 2 ZAP ext. added my 2 ZAP channel DIDs, my 2 trunks and my 2 inbound routes, my outbound routes as I would if I was using the zaptel drivers.

when the incredible install whipped all out, all I did was to edit again dahdi-channels.conf as above but I had to add
#include dahdi-channels.conf into the chan_dahdi.conf file.
reloaded everything and all worked again.

I hope this helps someone, I spent a good amount of time trying to read the MANY ways to get dahdi working.
perhaps someone can point me to a setup fully dahdi where I can add a dahdi ext and a dahdi trunk in free pbx, as of now all I see is No Unused DAHDi Channels Available when I try to add a dahdi ext…. more to learn…

[WM: Just plug in your credentials to the existing axvoice trunk, and you’re done!]

[WM: Not yet, but soon.]