oddball televideo problem

From: Kevin Handy <kth_at_srv.net>
Date: Thu Jan 15 11:15:09 2004

Jay West wrote:

>I have a system that does an "autobaud" when you hit return to log in. If I
>hook up a VT220, it works at 7/1/E, 8/1/N, 7/1/O, etc. etc. no problem. If I
>hookup a Televideo 950, hitting return gets no response at all. This is NOT
>a DTE vs. DCE problem, because the televideo does work with the same system
>on a different type of serial port.
>
>I was thinking something might be brain damaged with parity
>generation/checking on this terminal. Is this a known issue of TV950's?
>About the only way I can find out whats going on is to dig out my datascope
>and see the start data & stop bits between the two when hitting return and
>see what is different.
>
>Any thoughts?
>
>Jay West
>
>
I've had problems in the past with voltage levels on RS-232.

One device runs -12/+12V, the other 0/+5V, and they refused
to talk bi-directionally. Putting in a homemade level shifter
(forced the 0/+5 to -9/+9) made it work.

I think this may have been Televideo widgets to a Vax/3100, iirc.
Received on Thu Jan 15 2004 - 11:15:09 GMT

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