Land lines are getting hard to find these days. Almost as hard to find as old modems.
Back when I was a kid, I wanted to play a network game between two computers in my own house. I achieved this by hooking the modems up in a daisy chain. One modem plugged into the phone line like normal. On the ‘out’ port of the modem, I ran another line from it to the IN line of the 2nd modem. I then had the 2nd modem call our home phone number – which caused our phone to ring, the other modem picked up, and they made their normal connection sounds and connected! I could then unplug modem 1 from the phone line and the computers stayed in contact without issue.
At the time, I thought I needed a dialtone generator or line generator. Little did I know, I could have done it with a simple 9 volt battery and the right sized resistor. Skip along to 8:25 to see how to wire them together.