H2H: What are the valid phone number formats?

We have implemented international telephone format standard E.164 to our H2H service and we now accept all international numbers

E.164 numbers are formatted [country code][area code][local phone number]
UK - [44] [20] [12341234]
US - [1] [415] [5552671]

RegEx Matching for E.164

You can also exclude 0 as the first character since there are no country codes that start with 0.

Please note, if you are unable to use a valid number (e.g, missing customer number), we can provide a temporary number to be used but this is to be discussed with customer support.

Please see this external link for more information on the E.164 standard.