serial port lockups (was 386 Xenix 2.3.1/vpix/Compaq 20 Problem)

[Dave Hammond]

In article <226 at ecicrl.UUCP>, clewis at ecicrl.UUCP (Chris Lewis) writes
of a problem where his system's terminal i/o hangs up continuously.

In article <173 at summus.UUCP> craigp at summus.UUCP (craigp) suggests that
the length of the terminal serial lines may contribute to the problem,
especially on AST boards.

I have also seen serial i/o on long RS232 lines (the RS232 spec
provides for <= 50 ft. lines) cause lockups.  The MOST offensive board
was the AST "4-PXN", however, I have seen similar problems on Arnet
boards and Computone boards.

In the cases of the Arnet and Computone boards, a line-driver was installed
on the long lines [shortening lines is not very feasable when the client's desk
was in place well before the computer :-)], which solved all problems.

In the case of the AST board, the only cure was quick and sure decapitation
[of the AST].  It was replaced with an Arnet, with no significant problems
since.

--
Dave Hammond
daveh at marob.masa.com