So, what kind of hardware would you use to access BBS's? PC compatibles? anything with appropriate hard/software?
What is the minumum possible sysreq?
That's pretty much it. Hardware you needed a computer, modem and a phone line. And then of course you needed a terminal program (software).
Virtually every kind of computer I can think of had modems available. Original modems were "acoustic" -- like the one in Wargames, where David Lightman had to directly place his phone receiver on top of the modem. There was a switch that had to be flipped in order for the modem to work. In 1981, Hayes released the Smartmodem which connected directly to your computer, and then your phone line plugged directly into the modem. There were both internal modems and external modems.
The first modem speed I remember was 300 baud, although I have read about 110 baud. At 300 baud, I remember it took several hours to download an entire disk worth of C64 games (180k). There was 300, 1200, 2400, 9600, 14.4k (14,400), 19.2k, 28.8k, 33.6k, and 56k speed modems (maybe some others I'm forgetting, those seem like the main ones). Your modem could always step down -- in other words, you could call a 300 baud board with your 1200 baud modem. If I remember correctly, I remember downloading games on my PC and being able to download 8 1.44 floppies per hour at either 28.8, to give you an idea on the sense of speed.
Different computer models could connect to one another of course, but you usually had a better experience calling a BBS of the same type system. C64 boards sent colors and graphics to C64 users that might look like gibberish to Apple or PC callers. I know PC boards did the same, and I'm sure Apple boards probably did too. Another annoying feature was that the Commodore 64 was only 40 columns, so calling 80 column boards (and posting on them in 40 column mode) was often a pain for everyone involved.