DMX, Ethernet and PoE

[Sparkie]

Our new console should be arriving in the next week or so (Strand Palette) and it's now time to purchase some additional bits. I'm installing a wireless access point for RFU and also laptop usage at the production desk. The clever thing to do now whilst I have some funds is build something in for the future - DMX over ethernet.

I am looking at getting a 16 port switch to handle networking but have a question about ethernet to DMX nodes. Obviously I should be getting a switch that supports PoE and cannot find all the information I need to make that decision. I've looked at the specs for Pathport and Strand but have come up empty on what may be a crucial factor in determining which switch to buy - what are the power requirements for these nodes? Not much good forking out for a switch that supplies 4w per port and the node needs 6w.

I'd also be interested in hearing your comments about combinations that work (or more importantly, don 't) for you.

[Footer]

From what I have been told, strand does not want you to use off the shelf POE switches. What they suggest is to go with 3com power injectors and then patch into a standard 24 port switch. There are some issues with how some power injectors work with the SN110 nodes. I have personally bought an injector that does not work with the nodes that is compliant to the PoE standard. Call your local strand rep or the strand mothership and ask what injectors they install. I doubt it will be a powered switch. I will take a look in our rack at some point and see what is in there.

[jmabray]

This is because the Strand nodes don't meet the standard, not the power injector or POE switch.

As for POE switches, the ones that I have dealt with have all had an overall power rating (i.e. can supply 90 watts over the switch) not a per port power rating. So unless you are going to have a poe switch that is fully loaded (i.e. something on all 24 ports) It's not really that big of a worry.

I would talk to strand though. Since you have made the decision to use their equipment, the should be willing to tell you what devices you need to make it work right.

Jeff

[farmerjo1111]

ETC recommends and uses the LINKSYS/SRW224P for any Ethernet that requires POE. I would defiantly contact Strand and see what they say, they may have tested a couple of variety of switches or POE injectors. If your looking for POE injectors another company to look at is called Powerdsine.

Dustin Strobush
ETC Systems Group

[SteveB]

[QUOTE=farmerjo1111;56272]ETC recommends and uses the LINKSYS/SRW224P for any Ethernet that requires POE. /QUOTE]

I purchased this same unit for my Net2 system a year ago. ETC used to recommend a Cisco PoE, so the Linksys (same company) recommendation is new. In any case it's a rock solid unit and has never caused me issues.

Steve B.

[koncept]

i would still go with a poe switch as it may be useful for things like your access point and other nodes down the road, (if money is an issue leave it out...) but then i thought of my high school and the terminal strip splices used to inject power to the nodes. I didn't like what it looked like and thoght there were better ways but thats what we got....

[SteveB]

[QUOTE=SteveB;56274]

Originally Posted by farmerjo1111

ETC recommends and uses the LINKSYS/SRW224P for any Ethernet that requires POE. /QUOTE]
I purchased this same unit for my Net2 system a year ago. ETC used to recommend a Cisco PoE, so the Linksys (same company) recommendation is new. In any case it's a rock solid unit and has never caused me issues.
Steve B.

As a follow on, I kept my non PoE switch for all those devices not needing PoE, such as the Emphasis/Express system, all the Sensor CEM+ racks, Unison and the laptop when used as a remote console. The PoE switch lives right underneath the regular switch and simply connects specified lighting e-net connections. Not all devices like PoE, and I have certain e-net taps throughout the theater specifically labeled as "Lighting Network - Powered Port", but can re-patch to a non powered port as needed.

SB

[Footer]

[QUOTE=SteveB;56316]

Originally Posted by SteveB

As a follow on, I kept my non PoE switch for all those devices not needing PoE, such as the Emphasis/Express system, all the Sensor CEM+ racks, Unison and the laptop when used as a remote console. The PoE switch lives right underneath the regular switch and simply connects specified lighting e-net connections. Not all devices like PoE, and I have certain e-net taps throughout the theater specifically labeled as "Lighting Network - Powered Port", but can re-patch to a non powered port as needed.
SB

PoE "as standard" should not affect anything that does not take PoE that is on the line. It should be auto sensing, and if no resistance is felt across the pins, nothing goes out.

[koncept]

you beat me to it footer.... To add to that there are both non standard and standard switches/injectors out there. from the sounds of this discussion you need a non-standard injector that just puts power out there. if you were to use a standard injector it would wait till it detects the device and then turn it on.

We have poe switches in the office I work in, and as footer said they wait till they detect a poe device. my laptop is a great example (too bad i cannot charge it w/ that poe) it does not draw any power but if I plug an ap into the same port it would.

[SteveB]

[QUOTE=Footer4321;56323]

Originally Posted by SteveB

PoE "as standard" should not affect anything that does not take PoE that is on the line. It should be auto sensing, and if no resistance is felt across the pins, nothing goes out.

I was following the advice of ETC tech support concerning non PoE required devices (I believe their 4 port portable node was one they advised not sending power to) and in any event had more devices and taps on the network then the 7 ports on the PoE switch supported, thus needed to use both switches.

SB