Hi Iraiam,
Yes the ArcNet Card is a PCI or PCIe slot based, in the above case i have put forward. The thread initiator's card could be ISA based...
In your case when they upgraded the data server they would have also used the dll files provided by the USB Arcnet converter manufacturer.
If you try to unplug that USB arcnet brand and use another brand, your data server programs wont work any more for Arcnet data collection and hang unless it is reprogrammed to use the new dll provided by the new brand you would like to test. Here i am assuming that your Data Server is on Windows Platform and is greater version than WIndows XP (Windows 7 , 8, 10 Etc). If it is in an another operating system then the issue may be different. The reason being that Windows stopped supporting arcnet in their NDIS driver (Kernel driver) after Windows NT. I am also exploring for a kernel driver which can be generic....i wish the Arcnet committee had taken care of such standards and not ignored , i.e if they exist at the first place...
Please feel free to correct me and also share your views.