There has been a telnet BBS resurgence
There are a lot of BBS out there now, actually. We're in something of a resurgence. The systems are just accessed via telnet, but often are running on vintage hardware by way of a bridge device. I rotate the system I use to "dial in" between Amiga 1000, Apple IIe, Atari 520ST, TI-99/4A, Apple //c, Apple IIgs, and a "new" Tandy 1000HX I setup over the holidays specifically to use as my main BBS-riding machine. Some of the BBS I frequent presently are:
Level 29 ( bbs.fozztexx.com ), Black Flag ( blackflag.acid.org ), Particles ( particlesbbs.dyndns.org:6400 ), A80sAppleIIBBS ( a80sappleiibbs.ddns.net:6502 ), Cottonwood BBS ( cottonwoodbbs.dyndns.org:6502 ), Heatwave BBS ( heatwave.ddns.net:9640 ).
I talk a bit about my BBSing in this post (among others) on my blog: https://bytecellar.com/2017/05/30/the-wonderful-wifi232-bbsing-has-literally-never-been-easier/
Some of these BBS have an actual dial-up line as well, but most are telnet only. Try it - it's great fun!
bp