I believe ntalk has 2-way split windows as well. I think that's what I have installed on my Linux server, and a couple of my friends have accounts there too.

Ntalk is my second favorite way of communicating after in-person face-to-face talking.

i used ytalk to talk to my grandmother in the '00s. i would log in to her computer from the other side of the planet and start a session to see if she was on the computer. and then we'd chat.