I highly doubt this is an ethernet network card.

The chips & layout correspond to an IBM3270 interface adapter "Short ISA 3270 74F5175 " https://www.ardent-tool.com/comms/3270.html#3 … A_Short_74F5175

You can not use this card to network your 8086 and 286 together.

edit: These cards are used for connection to an old IBM 3270 mainframe.

It will be far easier to find ISA card with RJ45 socket (3c509 for example) which can work in 8 bit slot,
because for BNC-only you need:
- (old) Ethernet hub with BNC connector to connect it to existing network,
- 50 Ohm coaxial cable,
- 2x T-connectors,
- 2x terminators
https://en.wikipedia.org/wiki/10BASE2

Ethernet options for old DOS-machine (8086, 8-bit isa, serial and parallell ports)
https://forum.vcfed.org/index.php?threads/3co … -tpo-isa.14747/

Thanks a lot for repling.....I though it was a LAN card for PC....sorry

Yesterday I putted on ebay this mysterious isa card 8 bit.
I don't know what is it, but I'm sure you know....what's it?
Thanks !

That also, is not a NIC.

This, however, is.

https://www.ebay.com/itm/325848775649?hash=it … %3ABFBM5pjWmaRj

It has an AUI connector, if you really really need RJ45. You will need an external tranceiver module if you go that route.

This is an (overpriced) example of an AUI external tranciever module, that can work with RJ45.

https://www.ebay.com/itm/225430002215?hash=it … %3ABFBMltrpmaRj

However, for BNC only network, you dont actually need a hub, unless you are connecting to an RJ45 mixed network.

The minimal req for 10base-2 thinnet, is a section of BNC cable, 2 T connectors, and 2 80 ohm terminators.

If you intened to create a 10base-2 / 10base-T mixed network, the most cost effective solution is a mixed mode hub, like this one.

https://www.ebay.com/itm/296006976638?hash=it … ABk9SR4rMhZqkYw

You place a T connector on the BNC connector, and add it to the terminated 10base2 bus, like it was just another node. RJ45 network clients can talk and see the 10base2 segment just peachy afterward.

Bear in mind that 10base2 is very low speed, and will greatly reduce network performance, unless it is kept behind a switch.

mig81 wrote on 2024-01-19, 11:13:

Yesterday I putted on ebay this mysterious isa card 8 bit. I don't know what is it, but I'm sure you know....what's it? Thanks ! […]
Show full quote

Yesterday I putted on ebay this mysterious isa card 8 bit.
I don't know what is it, but I'm sure you know....what's it?
Thanks !

This should've been asked in a different thread.
204620156834

from the text on the card I'm inferring that it is some kind of card that picks up some italian weather station information.
edit: looking at the date codes of the chips (1986-1987), likely from the late 1980's or later.

Oneday I'll do a simple lan with bnc card, if possible between just 2 old pc...now I could try between 2 pc with 2 isa 16bit lan bnc/rj45 I already have....could be a start...

mig81 wrote on 2024-01-19, 12:12:

Oneday I'll do a simple lan with bnc card, if possible between just 2 old pc...now I could try between 2 pc with 2 isa 16bit lan bnc/rj45 I already have....could be a start...

Yes sorry man...I just don't want to pollute the forum...

mig81 wrote on 2024-01-19, 10:23:

Thanks a lot for repling.....I though it was a LAN card for PC....sorry

It is a LAN card, just not an Ethernet LAN card.

When you go to stuff this old, it's not safe to assume everything conforms to the same standards everything uses today - even if the connector looks familiar. Back in the 1980s, Ethernet was just one of many networking technologies. You had ARCNet, Token Ring, LocalTalk, EcoNET to name but a few as well as a number of these proprietary mainframe connectivity things.

Now, as for Ethernet, there are a lot of cards, and BNC connectors were indeed commonest. To connect two computers with Ethernet via BNC, you need the cards themselves, 50 Ohm coax with BNC connectors, but also two BNC T-connectors and two BNC terminators. The idea is that Ethernet with BNC is a bus that must be terminated at both ends, and unlike other technologies that need termination, like SCSI, the cards don't offer that termination. You use the T-connectors to connect computers to the bus. coax between them and then those terminators on the end.

Note that any break in the chain will bring the whole network down. Also note voltages are quite a bit higher than with UTP - don't put a live BNC connector in your mouth (and don't ask how I found that one out 😜 )

BNC coax networks are quite a pain and it's no coincidence Ethernet only started to become dominant after UTP was introduced. To connect a BNC network to a UTP network, you need either a transceiver or a bridge. A transceiver is a layer 1 device, taking the physical signals of one type and convert it to signals of the other type. By default they are bi-directional. A UTP hub with BNC port is acting as a tranceiver, and is probably the easiest way to do this. Note that you still need the T-connector and terminator for the BNC connector of the transceiver. A bridge is a layer 2 device, that actually takes the frames off the one network and retransmits them on the other. This has the advantage of isolating two separate collision domains, but the disadvantage of adding a bit of latency. A computer with two NICs configured to bridge them is the easiest way to do this.

Now, I actually have a box of cabling, connectors and terminators for this stuff, as well as a dedicated transceiver, so I could run my vintage stuff - or at least the older ones - using BNC. And I've used this stuff back in the day including being sysadmin for a network built on it, so there's a clear nostalgia factor. Still, it's in that box not doing anything. It's just too fiddly and my setup is so network-dependent (all systems are networked and I use FTP to distribute files to the systems) I don't want the hassle.

Instead, I just use UTP NICs. Now, 8b ISA NICs with UTP are pretty rare and if you find them frequently pretty crap (3Com Etherlink I or II...) and they tend to be very expensive too. So what do I use in my XT? An Intel 8/16 LAN adapter. It's 16b ISA, but as the name suggests, operation in 8b ISA buses is explicitly supported. It's a solid card, and is supported by mTCP - and is common and affordable; there's one on a well-known auction site for less than EUR 20 at the moment (and another in US for less than USD 20).

Edit: whoops - see that wierd_w already mentioned almost all the same points on BNC networking while I was slowly (at work...) typing this post.

wierd_w wrote on 2024-01-19, 11:59:

That also, is not a NIC. […]
Show full quote

That also, is not a NIC.

This, however, is.

https://www.ebay.com/itm/325848775649?hash=it … %3ABFBM5pjWmaRj

It has an AUI connector, if you really really need RJ45. You will need an external tranceiver module if you go that route.

That's the original 3Com Etherlink, which is described in various places (including in its Linux driver code) as 'braindead'. It drops received data when it starts to transmit, so can be considered utterly unreliable. To quote from the Linux Ethernet HOWTO:

This obsolete stone-age 8 bit card is really too brain-damaged to use.
Avoid it like the plague. Do not purchase this card, even as a joke.
It's performance is horrible, and it breaks in many ways.

And that's hardware-related, so just as relevant under DOS or any other OS you might want to run.

So even if you want to do 8b ISA BNC, that card is about the worst choice out there.

Interesting. I got in the game much later, and used etherlink III 16bit cards. They were well supported and worked well, from my experience.

Sad to hear their predecessors are braindead.

mig81,

Do yourself a favor. If you are a novice to networking don't start playing the game on "hard" mode.

Get one of these cards to start:

• NE1000 or a clone
• NE2000 known to run in an 8 bit slot
• 3C503
• Intel EtherExpress 8/16
• Anything that has a DOS packet driver (look it up before you buy)

In particular, this card is new, well designed, and can be purchased today: https://www.tindie.com/products/weird/isa-8-b … net-controller/ . (Well, when it comes back in stock.)

Do not buy the 3C501. It might work but it's reputation says all you need to know about it. I just got my first one this week and I'm going to test it to see how bad it is.

BNC networks are a pain in the ass. Start by getting an easier network set up first, then if you still like it branch out into the more esoteric things. Not everything with a BNC connector is Ethernet, and not everything with an RJ45 connector is twisted pair Ethernet, which is why I left off my favorite cards - the WD8003 series has some variants that have RJ45 connectors but are not Ethernet compliant.

If you do wind up with an older card that has AUI but not RJ45 you can pick up a CentreCom 210 adapter (external transceiver) for it. They cost about $20 and they bridge the AUI port to twisted pair.