[150925] in North American Network Operators' Group
RE: Digi TS8 serial console server funkiness
daemon@ATHENA.MIT.EDU (George Bonser)
Wed Mar 7 22:07:00 2012
From: George Bonser <gbonser@seven.com>
To: "ml@kenweb.org" <ml@kenweb.org>, "nanog@nanog.org" <nanog@nanog.org>
Date: Thu, 8 Mar 2012 03:06:04 +0000
In-Reply-To: <4F580BF5.20303@kenweb.org>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
>=20
> Other issues I've noticed..cannot use arrow keys to search command
> buffer.
This is going to be a tougher one. Might be a difference in character enco=
ding. Here is the VT100 spec:
http://www.handshake.de/infobase/dfue/prgrmmer/t322.htm
* ESC D cursor down - at bottom of region, scroll up
* ESC M cursor up - at top of region, scroll down
...
Arrows Standard Applications IBM Keypad
Up ESC [ A ESC O A Alt 9
Down ESC [ B ESC O B Alt 0
Right ESC [ C ESC O C Alt -
Left ESC [ D ESC O D Alt =3D
So you probably need to check your keyboard encoding. It likely differs fr=
om VT100 escape sequences.
Also, if you have several devices connected to that terminal server, see if=
you have one that is spewing debug or other information out the console po=
rt. That one might be causing some buffer overrun situations or keeping the=
CPU busy so it loses characters. Line noise can cause garbled data, too. =
But I would try flow control first. One thing I have seen before also is =
ground loops causing issues. Some serial devices actually tie signal groun=
d to chassis ground. If you have a cable connecting two such devices and t=
here is some ground potential difference, you can create a ground loop and =
introduce noise (and things like sparks, fire, blown fuses, etc.) if the gr=
ound potential difference is great enough between the two devices.
