AFAIK, the landline network has the ability to detect modems and change something in the codecs to make them work. Fax machines have relied on this for decades.
Really? Citation needed. My knowledge about landline codec (G.711) say that they do not "detect modems". I talk about landlines of modem/fax era, T1/E1 circuits.
Oh gosh, it’s just a random thing I read or heard somewhere ages ago.
I don’t know what the magic search terms are to find out accurately. (Every search result about codecs is talking about VOIP, making it hard to find the docs from before that.) The closest I got is this, which is already VOIP era:
https://www.eetimes.com/document.asp?doc_id=1201937Maybe that’s what I heard, but I thought something similar applied to the PSTN, especially for long distance, where heavier compression was used, but fax still worked.
Last time I tried (maybe 10 years ago) I could not fax from my land line anymore. The FAXes are a thing of the 80s!
You would think, right?? But apparently in some countries and/or industries, they’re still widely used, especially in jurisdictions where faxes are considered legal documents, but emails and other internet transmissions are not.
I haven’t had a fax-capable device (ignoring my vintage computers with modems) since the 90s when I was living with my parents, so even when I had a landline of my own (which also has been a long time), I never had a chance to try faxing on it.