OT strange networking problem

Having a problem with a windows XP pro SP2 networking problem thats
got me stumped. The network goes from a touchscreen which transmits a small amount of ascii based data less than one k/byte per transmition as its only sending a sequence number (label number) acessing a data base for a product registery then applying the weight data and sending that info to a datamax printer who already has all the necessary fonts for the different lables.

This is a tried and proven system with 8 years running with the older model of NOax touchscreen.
Problem is this I recieve these newer touchscreens try to connect via a fixed IP address (already checked to make sure its not a duplicate) when I connect I find that the autonegotiate for 10m/bit or 100 m/bit does not reliably work after experimentation
the only sorta stable connection I can maintain is at 10 m/bit half duplex. The line runns thru a data switch 10/100 M/bit
which we set the port to match the touchscreen settings of 10 m/bit. This then transmits to another data switch via a fibre optic tranciever (10 m/bit) All seems OK with the connection
in that there is no packets lost on ping tests however the minute the screen tries to send the sequence number I start getting excessive packet losses thats shuts down the application program. We had the Cat 5 line tested with a data acquisition tester and find no problems 70M effective 10/100 Mbit capability.

The data switch has 9 other touchscreens (older model that maintain stable connections) Thinking it was a faulty network adaptor we try another new style touchscreen and encounter the same problem.

Any takers? I'm at the point of considering that the problem
is the 10 M/bit fibre optic tranceivers (which we had repolished) or something to do with the response time after going thru several components.

Needless to say this has our IT dept at head office stumped as well as myself so any advise would be appreciated.

Check the RJ45 wiring again

I once saw a rj45 patch cable that was miswired such that it could make physical linkage but not pass data. A well meaning sparky made the cable without understading the need for the keeping the rx and tx twisted pairs consistent.

Checked that one already and confirmed with the data acquisition tester.

Similar Past experience

I have seen this exact problem in the past with my laptop network card. The "auto config port speed" would not work. Basically it would connect then disconnect repeatedly. I then tried to manually configure it for 10M full duplex, 100M full duplex, finally 10M half duplex was all that would work. I tried reinstalling the drivers and config software for the network card which did not fix the problem. Sensing that the network card was faulty, I sent it to IBM to be repaired. Got it back and viola it works

right now I'm trying to get a loan of 100 m/byte trancievers I've already tested this on a seperate fibre optic line bypassing the switch at 10 base t still have the same problem looks as though this network adaptor does not function properly at 10 m/bit unfortunately the adaptor is motherboard mounted and no spare PCI slot

What's the model of the NOax touchscreen? I'm wondering who makes their NIC and whether they have firmware upgrades. It would be worth contacting the manufacture at this point. Do you have another switch to test the new touchscreen units with?

Similar Problem

I had a similar problem with an industrial network where I had 3 Delta Tau motion controllers, three cognex cameras an Adept SCARA robot controller and a PC HMI all connected through a 10/100 industrial switch. The communications kept dropping out to the robot unpredictably. The only way I could get things to communicate reliably was to goto 10mb half duplex. It ended up that the robot controller (an old clunk-o'matic the customer provided) had trouble with the auto-negotiate handshake that the switch was implementing. I ended up having to partition it off on a separate NIC on the PC. OH JOY! - just another example of project "scope creep".

did some further tests, used two 10 m/bit fibre optic tranceivers and bypassed the switch had the same problem. trying to get a loaner of two 100 m/bit tranceivers to test its reliability at 100 m/bit. Other option is to find a usb or serial to ethernet adaptor as I have no ISA of PCI slots available. Its essentially the same scenario as you had Mcafone and I do believe its to do with the handshaking at 10 m/bit