Cobra II Net MAC Address

@ GHI Does each unique Cobra II NET caries the same (unassigned) MAC address?

@ RobvanSchelven - Yes, the default address

@ Mike - Thanks !

you can always use the code I just posted to generate your OWN…


@ Jay Jay - Nice work! Any side affect to use an online generator like this, if you know?

@ RobvanSchelven -
Side effects are many, you could be generating a one’s manufacturer’s MAC Address, second you might end up with an invalid Mac…

Please see the WIKI link i have shared in the code share to understand these issues…

Third you will have to use that online generator every time you need a Mac for a board… where using my code you don’t have to since it is automatic :slight_smile: and the Mac it generates are flagged as Locally Administered to the router…


@ Jay Jay - Thanks, I have read the pages of the links you provided. Does the random generator always return a unique code even when it starts with an equal string?
If so than the code is very useful.

A better option to be supplied by GHI would be to be able to buy a board or network interface with a MAC address. Especially if the board is used in a commercial applications

Not everyone needs a MAC, so it may be a problem for GHI.
There are (i.e. 25AA02E64 from chips for <30 cents with unique, registered MAC addresses for different protocols (I2C, SPI, etc.). These might be good if you are selling your products and want something permanent and definitely valid.

I agree, but the idea was that the user has an option to select from, something with or without MAC address

MAC addresses are only included with boards that have an Ethernet PHY chip. The G120 and G400 modules do not include a PHY chip. The EMX module does/did.

If there is a PHY chip on the board, then there is an E socket.

If someone wants to use the Cobra II NET in a commercial application it would be desirable or maybe even obliged to have a ‘legal’ MAC address

Buying a block of 4096 MAC address is a bit expensive if you only need a few.

For a few, it would be less expensive to buy a chip, extract the MAC, and discard the chip.

@ Mike - That’s a creative good idea. I will have someone talk to GHI directly since they probably already own a block as used for EMX. Maybe they can sell it as an addition to Cobra II Net.

@ RobvanSchelven - I believe the IEEE forbids just the sale of MAC addresses by a block holder. Sale of an address without a PHY with a board is a grey area.

It would be great if GHI would include the identity chip in all of their boards, i mean look they are cheap… $0.40 a piece…

Doing this would shoot two birds with one stone… it can be used as a unique serial number for board identity and for the MAC Address…

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