Can anyone tell me where does the network problem lie. I am trying to isolate the problem.

The configuration:
IBM laptop with a builtin modem. I upgraded to a internal modem/network from eBay since here is $550nz. This works fine with the modem and at work using a straight cable. It runs win2k pro. It is a 3Com 56k modem + Ethernet 10/100. When it works fine, I mean no dropouts and cable disconnects ever.

The drivers were obtained on the net. I obtained from MicroPC which the driver details says they are from 3Com. Model number is: 3cn3ac1556. The IBM drivers I could not use as they were locked into a certain model number of: 3cn3ac1556B.

The desktop. P200 with win95 and winNT 4 dualboot.

The issue lies when it uses a crossover cable between the 2 PCs.

Process (organized past to present):
What happens? Well, if the desktop uses a PCI 3Com 10 card it gets a connection. But it does take its time when you try to access the other PC to browse or to copy. The icon consistently says connect/disconnect every few secs at best. Over some time even with a 1MB file copying, network times out and cancels. If I use the cheapie PCI 10 network card the two PCs does not talk to each other. I can see themselves, but not each other.

I have also tried replacing the Cat5 crossover cable. All the cards was able to ping itself ok, but never each other. I manually configured IP addresses on the desktop for win95 and NT4, the IP addresses were confirmed by “ipconfig /all” and “winipcfg”. Win2k pro on laptop by default autoneg a IP address for the card.

Due to DSE’s refund policy I bought a PCI 10/100 card and also a PCMCIA 10/100 card.

1st: I installed the new DSE PCMCIA card and it worked like a gem. The desktop had a old 3Com 10 PCI card. I tried pinging each OTHER. It did not work. I confirmed their IP address … still. But they were sharing files, copying without delay at all.

2nd: I installed the PCI 10/100 (new from DSE) into desktop. The laptop had the new PCMCIA from DSE. Then the two cards could only see themselves and not each other.

3rd: I installed the old PCI 10 cheapie card into desktop. Laptop was using new DSE PCMCIA. Same thing as above.

4th: I reinstalled the PCI 10 3Com card back in desktop and it worked. Laptop was using the new DSE PCMCIA card as in #1 above. No cable disconnects and network timeout. Superb…..

Each of the above I never changed any settings. I simply swapped the network cards and rebooted the desktop computer. Drivers were installed prior. Similarly the laptop was tried with the builtin 3Com – kept dropping out. Then under real-time hot swapping I inserted the new DSE PCMCIA card and switched the LAN cable onto it and it worked immediately.

I do not believe it’s each of the motherboard or the cable since it was working in #1. Also, the RJ45 port of the builtin unit is not to blame since I have been using the builtin device fault-less at work. I have been installing the PCI network card on 2x PCI different slots on the desktop motherboard to no changes. Configuration - ?? With this eBay laptop builtin network card I cannot restart computer since it stalls at window screen. I need to shutdown and start-up again.

I obtained a firmware update 4.32. I have 4.30 now. I cannot use it since IBM software have detected my 3cn3ac1556 is not 3cn3ac1556B. I have called 3Com technical support they have told me to call IBM, but I bought this from eBay. IBM only use the B version. I was also told by 3Com the one I have is the OEM version.

I downloaded the latest driver from IBM. The difference with this one is it is able to be installed onto my device. The past ones, could not; so I resorted to the OEM MicroPC one. The results are:

Same as above the constant disconnect/reconnecting.

Any ideas appreciated…
Anyone know why a new DSE PCI and a new DSE PCMCIA cannot work together?? A tech told me once big names are more tolerable working with other cards.