IBM 3270 interfacing?

From: james <james_at_jdfogg.com>
Date: Sun Dec 5 06:16:56 2004

On Sat, 2004-12-04 at 16:13, Paul Koning wrote:
> >>>>> "Bj??rn" == Bj??rn <bv_at_norbionics.com> writes:
>
> Bj??rn> IBM 3270 used the EBCDIC control codes for their documented
> Bj??rn> purpose. HP 2645 terminals had an option to run multidropped
> Bj??rn> using an almost identical protocol. This protocol is half
> Bj??rn> duplex.
>
> That brings back some nightmares... the ugliest protocol by far I ever
> worked on was the one used by Harris 2200 newspaper display editing
> terminals. Bisync, half duplex, multidrop, using a PDP-11 DL11-E
> async line at the host end. Bletch. Naturally, the driver would mess
> up only during the midnight to 6 am shift... and I got to debug it
> while the composing room foreman was waiting for things to be put back
> into working order.

The simplest protocol has to be Burroughs Standard Poll Select. Imagine
daisy-chained RS232 and a polling sync or async protcol using ascii
control characters/words. I did lots of conversions to frame relay using
Motorola routers with Poll Select.
Received on Sun Dec 05 2004 - 06:16:56 GMT