IBM 3270 interfacing?

Date: Sat, 13 Nov 2004 11:13:53 +0100 From: Tore S Bekkedal &lt;toresbe(a)ifi.uio.no&gt; Subject: IBM 3270 interfacing? To: cctech(a)classiccmp.org 3270 terminals use... 3270 protocol, at the lower levels, to send noises down a coax wire. At the higher levels, you get into heavy-duty blue-glue acronyms you don't want to touch with a condom-covered bargepole. Like BSC, SNA... <shivers>. Here's the trick. These 3270 terminals hook up, not directly to hosts (well, except for a few special cases), but to terminal controllers. The least ancient of these are type 3174 - search ebay for IBM 3174* and you'll find a few usually. 3174-2x are best. Pay $10-$50 perhaps. These normally hook up directly to mainframes, via bus/tag channels or escon, or remotely to mainframes, via modems and wierd IBM protocols. You want nothing to do with either. The 3174s also came with options for token ring (pretty cheap now) and ethernet (still ruinously expensive) attachment. Get one of those, and get the latest version of the controller microcode (C6.4 I think) from IBM. This magic microcode allows you to also use the 3174 as a telnet client - you boot the controller, power on any coax-attached 3270 terminals - and the terminal displays a screen which essentially allows you to type 'telnet <hostname>' and connect, like any other telnet client or serial terminal (but with a funky keyboard!). See http://www.corestore.org/emuterm.htm for some my adventures with this stuff! Mike http://www.corestore.org