I posted this over on the PIAF forum just now. Pick up zap extension and dial *01 (or any other *0 speed sequence). Fast busy. Nothing even shows up in the log. I ended up groveling through the chan_zap.c code in asterisk (1.4 and 1.6 are the same). It has a ton of checks for various * codes, including apparently a check for ‘*0’ which seems to be related to some kind of 3-way calling deal. Since I am not in a call, this fails 
I assume when the speed dial module was written, the developer was not using a zap extension Is there a way to change the *0 prefix? When I go to the feature codes page, the star codes themselves apparently are read-only, so I can’t change them there. Speed dial is not a killer for me, but it would be nice if this worked for ZAP…
http://www.voip-info.org/wiki/view/Asterisk+vertical+service+activation+codes
So, this is why this was happening under the sheets and I wasn’t seeing anything in the log Now, that begs the question of why it even does this in the zap driver
It does this for pass through access to CLASS features on Analog trunks.
You can change the speed dial code in the features, did you uncheck the box next to the code so you can modify it?
my family, unfortunately, have been trained to use the *0NN numbers What I was wondering was: since freepbx seems to generate dialplans that implement the various star codes, why does zaptel/dahdi need to get in the way? I’m guessing I must be missing something? Alternately, the fact that there seems to be no way to disable this is frustrating - keep in mind, this is NOT on the fxo end, so if I have fxs ports inhouse, but the trunks are voip, this screws me for no gain, no?
I’m perfectly willing to change the speed dial prefix if that is the only way around this, I’m just mystified that the zap/dahdi drivers have this “feature” that apparently can’t be disabled or compiled out.
i’m assuming there is no (good) way to tell chan_zap to keep its fingers off the star codes, so i changed the speedial prefix