1 Topic by mpfletcher

  • mpfletcher
  • AV Engineer
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  • From: Signal Solutions
  • Registered: 2008-12-30
  • Posts: 24

Topic: DMX over Cobranet (485 port on CAB 4n)

We have two 4n's installed to bridge audio between two locations, we are also looking to bridge DMX between the two locations. I know nothing about DMX, but in reading up on the basics, I see it is physically the same as EIA-485. I know the 4n's have 485 ports that support serial bridging, so we are wondering if it would be possible to transmit the DMX signals over the 4ns' serial ports?

Has anyone done anythng like this before? Does anyone with DMX experience think it would work?

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2 Reply by JoshM

  • JoshM
  • JoshM
  • Recording Engineer at Burnt Orange Studio
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  • From: Meridian, MS
  • Registered: 2007-08-13
  • Posts: 1,498

Re: DMX over Cobranet (485 port on CAB 4n)

Hi Michael,

Yes, DMX-512 is a specific type of EIA-485 network. In theory, yes it should work. However, I've never actually done it before, nor have I heard of anyone doing it before. I'd suggest giving it a try and letting us know how it works. Be sure to let us know specifically what you had to do to make it work. The baud rate for DMX-512 is something odd like 38,xxx... you should look up that information and make sure that the CAB's will support the baud rate and number of data bits before attempting to implement it.

Good luck out there!

Josh Millward
Burnt Orange Studios

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3 Reply by mpfletcher

  • mpfletcher
  • AV Engineer
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  • From: Signal Solutions
  • Registered: 2008-12-30
  • Posts: 24

Re: DMX over Cobranet (485 port on CAB 4n)

Thanks Josh. I also neglected one detail. The 4n's are on seperate VLANs. Is there an XDAB of sorts for serial communication or would the 4n's have to be on the same network segment?

Last edited by mpfletcher (2012-10-02 20:02:02)

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4 Reply by JoshM

  • JoshM
  • JoshM
  • Recording Engineer at Burnt Orange Studio
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  • From: Meridian, MS
  • Registered: 2007-08-13
  • Posts: 1,498

Re: DMX over Cobranet (485 port on CAB 4n)

Oh, yes, that is a complete non-starter.

The two CAB's definitely need to be able to see each other on the same layer 2 network. If you have them separated on different VLANs, they will not be able to share serial data as it will not be able to jump through routers. It is all layer 2 traffic and based on MAC ID's.

Josh Millward
Burnt Orange Studios

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