[SR-Users] Re: Assistance Needed: Converting 11-Digit US Numbers to E.164 in Kamailio

On May 31, 2024, at 9:20 AM, Ben Kaufman via sr-users <sr-users(a)lists.kamailio.org> wrote: Answered in order of easiest answer to most complex: No. I've never encountered any US number requiring a prefix of "0" nor a US number being written that way. The USA is in the North American Numbering Plan (NANP). This includes USA, Canada, much of the Caribbean (Cuba, Jamaica, Barbados for example), some US territories in the Pacific (Guam, American Samoa). The NANP's "Country Code" is 1. In the USA and Canada (I think the entirety of the NANP) this is followed with a 3 digit area code (National Destination Number) followed by a 7 digit subscriber number. There is no consistent answer. Consider that the oldest phone network is in the USA, and the unplanned initial growth and many historic regional governing bodies it varies massively. It has also changed greatly over time. GENERALLY speaking people will use the 11 digit number or the 10 digit number (without the "1" country code), but there's not a lot of rhyme or reason as to which is preferred in one case vs another.