Simplest hardware node

Oh, that's what you mean.

A 10baseT transceiver and a power supply should do it.

-- glen

Thanks for both response;

I'm actually looking to expand this project slightly, do you know of anything even simpler (in terms of hardware, not effort) that I could do, say with a bread board?

bothered to reply."

That's a good point, James thank you, I won't do that anymore.

Or a cheap hub or switch. They might be more readily available.

BTW, please don't request an e-mail reply for a question posted in the newsgroup. If you can't be bothered to check back here, we can't be bothered to reply.

Are you sure a router would actually dump data to a hub or switch without any other connection ?

I would expect some ARP requests --at most--, but no payload :-)

Something like UDP or ICMP would work fine, as they don't require a "connection" to the other computer, the way TCP does. All they need, is a working network connection and they don't care what's beyond.

On 23 Nov 2005 22:17:19 -0800, bmearns blurted:

HTH Spamming this account signifies your unqualified consent to a free security audit

James Knott wrote: (I wrote)

He ask for the simplest. I have heard of people powering a transceiver off a standard 9 volt battery, though probably not for very long.

I used to know a machine with automatic AUI/10base2 switching which relied on a minimum current through the AUI power pins to do the switching.

It is probably now so hard to build the logic to generate link pulses, but transceivers are already designed to do that.

-- glen

Sorry, but that's not what I meant. Your 'connection' is a logical one. I was refering to the lack of a physical connection.

UDP or ICMP need a link to travel on. I think :-)

Think 127.0.0.1. Always connected, never a signal :-)

Or, if he can find one, and old 10base2 NIC, a T coupler and a pair of terminators should do it too. He could also use a 24 ohm resistor, in place of the coupler and two terminators. Can't get much simpler than that.

It seems to get simpler and simpler :-)

But how would an ancient NIC (unpowered ?) and a 24 ohm resistor been recognized (as a node) by a router, let alone tempt it to transmit data ?

I would assume that if he's trying to send data, he'd have a NIC somewhere. If he can plug in a 10base2 NIC, that should do. It gets the power from the computer. All he needs is a NIC of some time that's connected to a real circuit. With twisted pair, that means he needs a switch or hub to plug into, with coax type NIC, he only needs the proper termination.

Maybe I missed something, but I believe most 10baseT devices won't send data out unless they see link pulses coming in. A source of link pulses can be convenient in testing. One can then do whatever one wants with the bits coming out from the device.

-- glen

He wants the cheapest device that will lure his router into sending actual data to it.

I can only see a NIC qualify his needs if this NIC is placed in a more or less fully functional PC. Am I missing something here ?

I said 10base2, which is the old coax type ethernet. IIRC, it doesn't use a link pulse. However, a baseT connection to a hub or switch should be OK as the link pulse is use to check the connection to the hub/switch, not to verify there's another computer on the network .

He needs a NIC of some type. All we've done is suggest some possibilities. He has to use some common sense. I'm not saying he has to use 10base2. I just offered it as a simple, cheap possibility. If he has such a NIC and a computer that can take it, great. If not he has to look at some other alternative.

I hate it, when some people try to impose restrictions that the OP hadn't mentioned.

With 10base2 you need the terminating resistor if at the end, otherwise just a tee connector to get the bits to fall on the floor, as the OP requested. For 10baseT you need link pulses.

One possibility is a device to indicate any traffic on the port, which the LEDs on many transceivers will indicate.

One problem is that the switch might not send unicast packets that direction, but that will be true in any case.

-- glen

In another note, I mentioned using a 24 ohm resistor, in place of two terminators and T connector.

I'm looking for the simplest possible hardare implementation that I

can

Hi there. I think you got some of this wrong. But on the other hand

there are a few things you acctually convinced me with. Can you add

more to that?