3com 509b is one of the best cards. Great compability, easy to configure and supported by almost everything.

If I had both sitting on my desk and I was building a computer I'd grab the 3C509. If I only had an RTL8019AS handy then I'd use that. Both are fine cards and once installed and configured I doubt you'd really notice any difference between them even if the 3Com card is probably marginally faster. Both cards will be significantly slower than a more modern PCI ethernet card.

If you need drivers for a Realtek card, Realtek still provides them for a pile of operating systems here. If realteks website gives you trouble I've made a copy of them over here. For a 3Com 3C509, drivers from either here or here should work. I'm not really sure what the difference is between the two sets - I think I used the 3C5X9 drivers (second link) most recently. The 3Com drivers are, IIRC, self-extracting EXEs but you should be able to open them with 7-zip as though they were regular archives.

3C509B is a card. RTL8019AS is a chip that was implemented on many cards. Exact features of cards can vary - although generally the same drivers will work.

That aside, agree with all the above: the 3C509B is an excellent all-rounder - but RTL8019 cards would generally be a very good second choice, particularly with OSs that did not exist around the time 3Com ceased operation.

Both are decent chips/cards, the Realtek chip is newer and might work better with Win9x if full PnP is required. I have one RTL8019A based card that has design issues, namely the TP transformer is missing some capacitors to GND. This causes the card to not work well with modern 100Mb (or faster) network switches, you have to either mod the card or dumb the link down to 10Mb by using older Etherned hubs. Not every card will have these issues though.

Debian 1.1 supports 509B directly in kernel, while all NE2000 class cards like 8019A require a module to be loaded, for which you need to know the cards base I/O address. Both will work though. On the other hand I found that with 509B it's best to manually set the interface type rather then use auto setting, it seems quite unreliable at detecting the cable - at least on my setup. Also, full duplex on TP will not work in auto mode on 3Com, that is HW limitation it seems.

Agreed that the 509B is best set manually, which also helps it play nice with sound cards - sometimes with PnP the cards end up on IRQ 2/9 and/or 0x330 ,which is the default for MPU-401 MIDI. I generally like to put my NICs on 0x300 and IRQ 10. The full duplex thing is also very relevant for performance.

Deunan wrote on 2022-04-06, 08:45:

Also, full duplex on TP will not work in auto mode on 3Com, that is HW limitation it seems.

Full Duplex doesn't work automatically on any 10 Mbps card.
FD autonegotiation needs NWay, ie. 100 Mbps card.
With a 10 Mbps card, FD needs to be set manually on both the card and the switch.

The 8019 is a NE2000 clone. Should be the most compatible.

The 509 card looks, feels, smells and even used to cost the nicest. It certainly promises to be a work of art. What disappointed me the most about it, is the fact that I could not get it to do DMA transfers. If I remember correctly, the hardware only supports PIO.

My favourite isa network card is the SMC Ultra 8216T.

If I had to choose between 3c509 and an 8019, it would be a difficult choice to make. I would eventually just test both and use the one with the best throughput.

For DOS and Microsoft Windows the 3com3c509 is well supported.
The Intel Pro 10 is also a good ISA Network card with good support.

The problems I have seen with some network cards is that they don’t negotiate a speed well with some hubs, switches, or routers.
So they either cause the computer to hang or lock up. Sometimes the cards act erratically.

But I have had really good luck with the 3com 3c509b. It’s my go to ISA Network card.
It has worked with every thing I have tried even modern gigabyte switches.

The throughput of the 3c509 in comparison to the 8019AS is way better (measured in DOS on a 486).
You can easily compare that if you setup the mTCP FTP server and perform some file transfers.

Don't use file transfers; that just introduces another factor (your disk performance). If you are going to benchmark using FTP then do everything from a RAM disk.

I've found that most 3Com cards will outperform an NE1000 when used in an 8 bit slot. I suspect that is true for the 16 bit slots as well. NE1000/2000 works, but it's the lowest common denominator - Novell wanted cheap cards to help spread Netware, and it shows.

For those of you looking for new 8 bit NE2000 cards that work in an 8 bit slot, check out https://www.tindie.com/products/weird/isa-8-b … net-controller/ .

-Mike

3Com will get you some street cred while people tend to look down on Realtek.
But I fully agree with everyone else. Go with whichever works in your PC as overall it won't make much difference, File transfers being the only noticeable difference and 10mb will still feel slow (still better then FDD transfers though!)

Yeah, I think there are several completely good alternatives. I have currently three 3COM Etherlink IIIs and one SMC card (can’t remember the type) running on my 486s. I also have couple more Etherlink’s to spare. I can’t find any faults with either of them, but I’d say Etherlinks are easier to work with.

My default thing with DOS ISA and pre-USB storage compatible systems is to slap in a network card. It just makes life 100 times easier: no floppy hassle or burning stuff to a CDRW. Not all my systems even have optical drive, so I’m not keen writing bunch of floppy images on my modern PC every time I wan’t move data between systema. Network cards weren’t useful in home back in the day, but in modern world they nicely integrate those old systems with modern stuff.

I can see there are 3Com 3C509B models with external 8KB sram and ones without it.

https://cdn.shopify.com/s/files/1/0597/9131/1 … apter_1024x.jpg
https://cdn.shopify.com/s/files/1/0656/5003/2 … 80afdda5e44.jpg

The only difference I can spot is much later date-codes. Chip 1995/96 vs 2000, PCB 1994/95 vs 1997. Makes me think later one might have ram integrated in the chip to minimize manufacturing cost.