Does anything like number exist?
Yes, the tel, fax and modem URL Schemes are discussed in https://www.ietf.org/rfc/rfc2806 2.3 “fax” URL scheme The URL syntax is formally described as follows (the definition reuses nonterminals from the above definition). For the basis of this syntax, see [RFC2303] and [RFC2304]. fax-url = fax-scheme “:” fax-subscriber fax-scheme = “fax” fax-subscriber = fax-global-phone / fax-local-phone … Read more