What is Fax over IP?
Fax over IP (FoIP) is not the scanning of an image and transmission of the results to a remote end via the Internet. That would be e-mailing (the resulting TIFF file), or FTPing it, or sending the file via HTTP PUT. Or whatever. No, that would be very easy; the Internet was born for it, but that is not faxing.
Fax over IP is actually to interact via the Internet with a remote, regular (T30, PSTN) fax machine. The problem is, to exactly reproduce the characteristics of a PSTN electrical circuit via a packet network is almost impossible. Packets get delayed, they arrive out-of-order (for example, the third packet arrives after the fifth), they get lost (for example, the fourth and seventh packets do not arrive at all), delays ...
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.
Read now
Unlock full access