[Simh] HP Terminal emulators, MSKermit with DosBox, CKermit 9 to the HP3000

Tom Morris tfmorris at gmail.com
Wed Apr 13 02:14:03 EDT 2016


On Wed, Apr 13, 2016 at 12:28 AM, Clem Cole <clemc at ccc.com> wrote:

>
> ​Hang on -- BREAK is not in the old USASCII ​7 bit map.   As explained in
> RFC 854, it was a >>key<< on the old Teletype ASR33 (and the ATTEN key on
> the IBM 2741).   What BREAK did was sent a very long (i.e. 1 second if I
> remember correctly) "marking" time signal.
>

Huh? Definitely not an ASCII character, but where would an ancient
electromechanical device like the ASR-33 have kept this fancy 1 second
timing logic?

I'm pretty sure that the length of the break is whatever length you could
be bothered to hold the key (and thus the line) down. It was only in much
later models of terminals that logic got introduced between the BREAK key
and the line.

Tom
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.trailing-edge.com/pipermail/simh/attachments/20160413/3e79ef36/attachment.html>


More information about the Simh mailing list