7300 and 9600 baud modems

Gil Kloepfer Jr. gil at limbic.UUCP
Sun Nov 26 20:38:29 AEST 1989


In article <24425 at cup.portal.com> thad at cup.portal.com (Thad P Floryan) writes:
>without all the brain-damage.  In other words, DT80 mode does not have to
>send the humongous number of pad characters to accomodate the slow 8080
>in a real VT100.

The real VT100s have an 8037 micrcontroller (it's a preprogrammed MCU),
not an 8080 (at least mine doesn't anyhow...).  They do use some 8080-type
support chips though to do some of the work.

On an aside, this *is* the reason why the DEC VT100 is so slow.  The
VT220s I think might also use MCUs, but it's MUCH faster, and will
show 19.2K really well!

Also note, in line with what Thad has already said, using a terminal
on the UNIX-pc rather than the built-in display for just text-based
stuff, like reading the news, is definitely faster.  The VT100 I use
at 9600 baud (because of the speed problem) in the living room is
still faster than the 3B1 display!

A problem I *have* noticed is calling at Trailblazer speed to a system
from my VT100 *through* the UNIX-pc results in many lost characters
on my receiving end.  I'm not sure whether this is due to the 3B1 not
being able to handle 2 serial ports at high-speed, or the VT100 being
too slow and causing too many characters to be queued-up at the device
driver level.  In any event, forcing the Telebit speed to 9600 baud
doesn't fix the problem.

Gil.

-----
| Gil Kloepfer, Jr.
| ICUS Software Systems/Bowne Management Systems (depending on where I am)
| ...ames!limbic!gil



More information about the Unix-pc.general mailing list