ANI failure with E911 and Cisco Call Manager Express

Found out something really interesting... Typically ANI will only resolve if your outbound 911 calls have the billing phone number attached... so if your location has numerous DIDs, tag the outbound calls to 911 with the billing phone number. Also, if you have trouble faxing to some numbers (weird errors, etc...) it is likely that you are being blocked because of ANI funnies as well. I think some telcos block non-resolving numbers to prevent fax spam.