HP 7220C plotter port settings

Glen Slick glen.slick at gmail.com
Thu Dec 5 18:13:01 CST 2019



Page 195, Connecting the RS-232-C Interface

On Thu, Dec 5, 2019, 3:34 PM Jules Richardson via cctalk <
cctalk at classiccmp.org> wrote:

> Hi all,
> I picked up an HP 7220C flatbed plotter the other day which (after freeing
> the stuck carriage) is responding to panel commands in 'local' mode. For
> the terminal RS-232 interface, does anyone happen to know:
> a) The character size (7 or 8 bits)?
> b) If the connection between terminal and plotter is supposed to be
> straight through (i.e. 1:1 pin mapping), null modem, or something else
> entirely?
> I'm not sure if the plotter considers itself DTE or DCE, given that it has
> a modem output port (i.e. it sits partway along in the chain of things).
> Oh, there's a "conf test" switch setting on the back - does anyone know
> the
> purpose of that? I'm wondering if it's supposed to echo back to the
> terminal any data that's sent to the plotter, but that's purely a guess.
> Sadly there don't seem to be any docs online (or much in the way of any
> info, to be honest).
> thanks,
> Jules

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