802.3af Power Over Ethernet on the cheap

802.3af Power Over Ethernet on the cheap

Summary: Anyone interested in IP Telephony or remote video cameras that draw power over an Ethernet cable has to be interested in some cheap 802.3af PoE (Power Over Ethernet) gear.

SHARE:
TOPICS: Networking
4

Anyone interested in IP Telephony or remote video cameras that draw power over an Ethernet cable has to be interested in some cheap 802.3af PoE (Power Over Ethernet) gear.  Well I found just the thing with this AirLink 8 port 10/100 Ethernet switch with 4 802.3af PoE ports on sale for $30.  The device normally sells for about $60 which is still a relatively cheap way to get 4 PoE ports any way you look at it.  Here's what it looks like unboxed below.

AirLink 8 port 10/100 Ethernet switch with 4 802.3af PoE ports

You'll notice that it has a full PC style power connector which is unusual for an Ethernet switch of this size.  This is because each 802.3af standard PoE port theoretically draws a peak load of 15.4 watts which means the four PoE ports alone can draw 61.6 watts and the switch itself probably draws another 5 watts or so.  With 4 PoE ports, that means we can plug in 4 IP Phones which are getting amazingly cheap these days ($80 to $200) and the newer ones can even support wideband audio CODECs.  You can use the other 4 ports for uplinking, troubleshooting, or the small Asterisk PBX appliance.

You can't do advanced functions like VLAN separation on a cheap switch like this to separate your Voice devices from your data network but you can simply not connect this to your data network and use true physical separation between Voice and Data.  Even if you implement all the Layer 2 security lockdowns there is nothing like the reliability and simplicity of an air-gap between your data network and your voice network.  Although this does require you to run one set of cables for voice and one for data, switches that support data and voice on the same port cost 10 to 20 times more money so it still works out to be less money and you have the piece of mind of having physically separate infrastructure.  For small offices and even retail chains a device like this is the perfect solution.  At this price, you could forget about the support contracts and just get a spare switch at each location.

I'll be doing more IP telephony experiments so this PoE switch is going to come in real handy.

Topic: Networking

Kick off your day with ZDNet's daily email newsletter. It's the freshest tech news and opinion, served hot. Get it.

Talkback

4 comments
Log in or register to join the discussion
  • Beg to differ (of course, what else would you expect?!)

    "[i]You can't do advanced functions like VLAN separation on a cheap switch like this to separate your Voice devices from your data network[/i]"

    [url=http://www.geek-pages.com/articles/latest/dd-wrt_-_setting_up_a_separate/isolated_vlan_on_port_4_with_dhcp.html]fyi[/i], you can do VLAN on a cheap ($59) Linksys WRT54GL.

    But this whole Power over Ethernet is very intriguing not to mention quite useful--beats pulling cat5 thru the walls. ;)

    Thanks George for a good article.
    D T Schmitz
  • Resending: Beg to differ (of course, what else would you expect?!)

    "[i]You can't do advanced functions like VLAN separation on a cheap switch like this to separate your Voice devices from your data network[/i]"

    [url=http://www.geek-pages.com/articles/latest/dd-wrt_-_setting_up_a_separate/isolated_vlan_on_port_4_with_dhcp.html]fyi[/url], you can do VLAN on a cheap ($59) Linksys WRT54GL.

    But this whole Power over Ethernet is very intriguing not to mention quite useful--beats pulling cat5 thru the walls. ;)

    Thanks George for a good article.
    D T Schmitz
    • Not in the same way

      Voice VLAN separation is a bit different than straight VLAN assignment. You have to be able to support VLAN trunking on a single port. But thanks for your post.
      georgeou
  • You can trunk on the cheap routers...

    Actually you can do 802.1q trunking on the cheap routers... Check this out:

    http://www.geek-pages.com/articles/latest/802.1q_trunking_on_the_linksys_wrt54g/s/l_with_dd-wrt.html

    Kevan
    kevank@...