The main difference between US and International fax number formats lies in the use of country codes.
If you are trying to send a fax in the United States, then it should consist of 10 digits: the three-digit area code plus the seven-digit phone number. It would look something like:
212-823-7890
For this example, “212” is the area code, which is one of the area codes in the North American Numbering Plan (NANP) for most of the borough of Manhattan in New York City. While “823-7890” is the unique fax phone number of your recipient.
While North American fax numbers generally remain consistent in the number of digits used, those around the world vary widely. In fact, an international fax number could range from as few as 6 to over 9 digits.
When sending international fax, you will need to add additional information such as a country code and an international access code before your recipient’s subscriber number.
Depending on where you’re sending it, these codes can be one or two digits long (e.g., +1 for Canada or +85 for China). All countries have their own unique numerical prefix so that your international faxes don’t accidentally get sent somewhere else!
For instance, if you wanted to send a document to someone located in India with a local fax number 044 123 4567, your actual dialed fax number would be +91 44 123 4567 (+91 being India’s country coding prefix).
Generally speaking, each region will have its own set of rules regarding how to write out an international fax number correctly — some countries require hyphens or parentheses to separate numbers while others do not; furthermore, some countries require only one zero after their exit codes while others require two (or even three).
Additionally, different countries use different symbols and characters that represent local access codes; for example “00” is used by some European nations instead of “011”.
No matter what country your recipient is in though, always double-check with them first before attempting to transmit anything via fax just be sure that everything has been written down correctly.