OK Tkx - I see AEP uses an EDACS but is that the same as ProVoice EDACS? (My guess is not)
The only NXDN I see is what seems to be a towing company R.E.M.
Standard EDACS is analog, PROVOICE is a digital option on EDACS systems. However, don't pay extra for EDACS to listen to AEP, because as phask mentioned, the AEP EDACS system is being retired. AEP's new system is P25 digital, which comes standard on any digital scanner.
EDIT: And pretty much every EDACS system is going away soon, since it is no longer supported by the manufacturer.