[na-user] loop networks

k8cc k8cc <k8cc@mediaone.net>
Sat, 06 May 2000 09:16:47 -0400

At 12:17 AM 5/6/00 -0700, K2KW wrote:

>A tip if a computer has gone off line...  I make a few "loop-back" plugs
>from DB9/DB25's (the loop-back shorts TXD and RXD - pins 2 & 3?  I dont have
>my manual in front of me to be sure).  If a computer crashes, or you want to
>take a computer off line, just plug the loop-back onto the Y-connector
>feeding each computer.   The loop-back completes the network, so there is
>minimal loss of data among the computers that are left on-line.

This works real well.  At K8CC, we went a step further.  For our loop 
network, we brought serial cables from each computer to a central box in 
the shack.  The box ties all the serial cables together for the loop 
network through toggle switches so that any computer can be taken out of 
the network with just the flip of a switch.

We also added an LED to monitor the status of each serial line, like those 
inexpensive COM port testers you can buy.  A 2.7K 1/4W resistor and a 
dual-color LED is all it takes.  This is very useful for determining the 
network status at a glance, or for troubleshooting serial cables.  Its also 
fun to watch when a QSO gets logged, as you can follow (with the blinking 
LEDs) the QSO as it ripples around the network.



Submissions:              na-user@contesting.com
Administrative requests:  na-user-REQUEST@contesting.com
WWW:                      http://www.contesting.com/datom/
Questions:                owner-na-user@contesting.com