So I found this article:
https://itstillworks.com/how-do-i-send-a-fax-from-australia-to-america-10431.htmlIt talks about IP fax machines, which are basically more modern machines that support faxes over the web, but they also say this:
Analog fax machines can send Internet faxes with the appropriate T38 capable VoIP gateway attached, which allows them to connect to the Internet through the same protocol that VoIP phones do.
That lead me to find this device:
https://www.cisco.com/c/en/us/products/unified-communications/ata-190-series-analog-telephone-adapters/index.html (I found it for 100 pounds on Amazon)
However I also found this much cheaper one (38 pounds) -
https://www.amazon.co.uk/Dpofirs-Gateway-Network-Internet-Voice-over-IP-silver/dp/B09JBN2P1V - it says it supports fax!
So I THINK if you want to put an old fax machine online, you can do it for 38 pounds, which seems quite reasonable.
Next we just need to figure out if there's an easy and cheap way for people to do it if they don't have an old fax machine (and don't wanna buy one)
It seems like a lot of modern printers do support fax, this is a modern one that says it does:
https://www.amazon.co.uk/Canon-MG2555S-600DPI-printing-copying/dp/B01ICH52H8I don't know how that works though, so I think we need to find someone who has a printer with fax functions and figure it out and see how we can connect it all up! (Over something like Skype I guess?)
It's not very well documented, but it seems totally doable, apparently, a lot of government offices still use fax so the support is there for them!
EDIT: According to
this video it was not possible on Skype 14 years ago because compression on Skype was too extreme, but that might not be the case now.. As far as I can see you do need to have a virtual phone number though (those are never free) but you can get them from services like:
https://www.pamfax.biz/introduction/fax-number/ and they don't seem expensive (I think Skype also offer them? at least they used too)
Im still a bit confused about how it all connects, id have to see it function to understand