FoIP stands for “Fax over IP” or “Fax over Internet Protocol.” It is also known as virtual fax or internet fax.
Just as VoIP (Voice over IP) is a phone that travels over the internet, FoIP is fax that travels over the internet.
“FoIP” can mean any time of fax signal that partially travels over the internet. This includes online fax as well as IP-based internet fax communication.
The term “FoIP” is mostly used in terms of internet fax infrastructure. The term hasn’t reached mainstream usage that VoIP has.