How can I, either using the DAHDI freepbx module or editing a conf file set which T1 one card/span comes first?
I have three T1 cards, two of them are four ports and one is a single port. I would want the single port one to be the first span so it would start with channel 0, but the freepbx module set it for the last one.
Thank you
You can use module settings under FreePBX->DAHDI configuration to load only module which has one T1 as you want.
I am assuming this is first time you are configuring DAHDI etc and not done any changes from CLI. Else as per warning on the DAHDI configuration page, your changes done from CLI will be lost.
While wanting to control the system down to the bits might seem like a good plan, might I suggest that you not worry about where the spans come up in the config? The only place you’re going to need the channel information is in the configuration of your trunks, and since you control all of the information (and use the trunks to control the “first channel”), the actual order of the spans isn’t really important or pertinent to your operation.
I’m pretty sure you CAN do what you are trying to do with the DAHDI control module, I’m just suggesting that you go with the flow and let the system sweat the small stuff.
If you want guaranteed and explicit order assignment start with
and pay attention to the udev bits, BUT it’s a little complicated and you need to understand udev 
Also look at the “assigned-spans” configuration.