I have a system that has an old network card, supporting 10 Mbps Half duplex. Is there a way to "wrap" the system with a router or switch that will allow me to connect it to a 1000 Mbps full duplex network?

  • 2
    It would be helpful to know what network device you're trying to connect to. Some will negotiate down to 10 Mbps, and some won't.
    – Ron Trunk
    Dec 15, 2016 at 12:54
  • Did any answer help you? If so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you could provide and accept your own answer.
    – Ron Maupin
    Aug 15, 2017 at 16:50

3 Answers 3


The router/switch you are plugging into should negotiate with the card. If you are plugging into a managed switch, you will likely be able to hard code the port's speed/duplex. In a Cisco device this would look like so:

Switch# conf t
Switch(config)# int fa0/0
Switch(config)# speed 10
Switch(config)# duplex half

  • The actual way it works with a fixed interface, e.g. 10/half, is that negotiation doesn't actually happen. The interface that can negotiate detects, not negotiates, the speed, and it uses the default duplex for the speed (10/100 is half, and 1000 is full).
    – Ron Maupin
    Dec 15, 2016 at 16:14
  • This happens when the 10/half side is not running the autonegotiation protocol, so the switch/other side uses parallel detection (autonegotiation mechanism) to determine the speed. Is this correct? Sorry for the question within a question, I might open a new topic if it's appropriate.
    – stets
    Dec 16, 2016 at 13:58
  • This Cisco document has a table that explains what happens when a 10/half interface connects to an Auto/Auto interface.
    – Ron Maupin
    Dec 16, 2016 at 15:14

Have you tried simply plugging it in?

Many, even most, (but not all) gigabit ports will negotiate down there.

If the one you have won't, buy a small switch that will (look for specs like 10/100/1000 for the port speeds), and put it between slow old device and the rest of the network.

Alternatively, put a new(er) network card in the device.

  • 1
    It may be useful to point out that each switch port is a separate collision domain, so one port can be half duplex, while others are full duplex.
    – Ron Maupin
    Dec 15, 2016 at 14:03

I have done this several times (connecting 10M devices to 1G ports) and what I can tell is there is no rule for it, that could tell us in advance whether it will work or not. In theory, it should work, but some devices simply can't negotiate with the switch (or the switch with the device), which means that you will have to force the speed/duplex, just like the answer before.

Just plug in and make a test, just like the in first answer. In case in case it doesn't work, start forcing the speed/duplex and good luck!

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