POE injector with 20+ ports, recommendations?

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[H]F Junkie
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Jun 17, 2003
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I'm looking for a POE injector that has 20+ ports. Does anyone have any recommendations? Things they've worked with that they've liked, or have heard good things about?
 
Any reason why you don't want a 24-port PoE switch? A managed PoE switch will allow you to manage power where the injector won't.
 
We're running PowerDsine 24 port units on our Mitel phone system - they are almost 8 years old now and honestly have been absolutely 100% reliable.

Meanwhile I've had 2 HP PoE switches die in the past 3 months, and the Cisco gear (lowest end PoE equipment they make, some of it is Linksys branded) our telco supplies in out of town locations die on a regular basis (honestly, we had to convince them to leave a cold spare onsite because it was causing us such massive downtime).
 
goodcooper said:
do those things support gig switches? might be a good option for retrofitting offices that already have managed gig switches w/ poe....
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Midspans don't care about the data speed as all they are doing is inserting power on the unused pairs of cat5.
 
schnell said:
Midspans don't care about the data speed as all they are doing is inserting power on the unused pairs of cat5.
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GbE uses all pairs, hence the valid question. The answer is it depends on if the Midspan and consumer device support it.
AFAIK, PoE GbE requires 802.3af Mode A (Power over data pairs) where most (if not all) midspan injectors are Mode B (Power over unused pairs). Since GbE uses all pairs, at best a midspan injector would knock the data rate back to 100Mb; at worst it would not link. Damage should not be possible with 802.3af since the consuimer has to negotiate to receive power- no negotiation, no power.
 
You might have problems with a midspan that isn't rated for Gig, if you try and use Gig devices. Do it the right way.

Get a proper POE switch or get a gig capable midspan.

I've used powersdine, though I don't know how their stuff is now that they've been bought.

For single port injectors we've used Phihong, which are pretty nice.
They also have multiport units
http://www.phihongusa.com/html/midspans_15_4w_port.html

Mouser.com stocks them.
 
RocketTech said:
GbE uses all pairs, hence the valid question. The answer is it depends on if the Midspan and consumer device support it.
AFAIK, PoE GbE requires 802.3af Mode A (Power over data pairs) where most (if not all) midspan injectors are Mode B (Power over unused pairs). Since GbE uses all pairs, at best a midspan injector would knock the data rate back to 100Mb; at worst it would not link. Damage should not be possible with 802.3af since the consuimer has to negotiate to receive power- no negotiation, no power.
Click to expand...

I blew up a polycom phone by plugging it into an 802.3af injector that in turn was plugged into a Cisco inline power switch.
 
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