With our Mitel phone system when calling a non-District phone number using a Mitel desktop phone users are now required to first dial 9 (to get an outside line), then 1+Area Code+Phone number when making calls anywhere in the USA, this includes FAX lines, call forwarding, speed dials, etc.
Example: 91xxx-xxx-xxxx

On 10/24/2021 there was a Mandatory 10-digit dialing change in 82 area codes nationwide. Callers must dial 10 digits when making calls within the area codes listed on the PDF.