Clap On, Clap Off! Server Technologies Switched Power Unit

SATV recently got a device that will make our network a bit more reliable.  Over the past several years, we’ve seen hardware monitors (like the environmental monitors made by IT Watchdogs that I wrote about before) and remote reboot/remote power devices drop dramatically in price.  Devices that were once only in high-end data centers are now available to small shops and small budgets.

This is a Server Technologies CW-8H.  It’s around $350.  It has 8 outlets, a digital ammeter, and the most important part:  An Ethernet connection.

Each of the 8 outlets can be individually controlled from a web interface, Telnet, SSH or SNMP agent.  The photo doesn’t show this very well, but each outlet has an LED to indicate power status.

I asked for this device to solve a problem:  As more and more Ethernet-connected devices come out, a number of them have taken shortcuts in their management interfaces.  Some devices—hello, SMC 8014 cable modem!—are known to get flaky while in use. 

Unfortunately, some of these same devices—hello, SMC 8014, again!—either don’t have a reboot button on their Web interface, or else the same bugs that affect their operation keep them from being accessed remotely at all.

I and SATV still have painful memories of the time during a blizzard when our main network switch (an SMC model we’ll never use again) had a power failure, as did the rest of the building.  When power came back up, the switch kind of came back.

Sort of. 

It put us off the air.  

I came in a day later, after the storm had passed, thinking the worst (power surge killing every NIC in the building…)

I power cycled the SMC switch.  It came back up completely. 

I was livid!

Fast forward a few years later to this fall.  It’s Halloween season and we have a very popular parade that kicks off the season and is streamed online for the many Salem expatriates and Halloween celebrants.

During setup, I tested the video stream from one of our Macs to  It worked all morning. 

At a critical time in early afternoon, when my producer is trying to nail down our timeline, the stream stops working.  Panic.

I’m thinking Comcast blocked the port, as the problem was presenting itself.

Log into the modem.  Do tests.  Find everything’s OK past the cable modem. 

But remember I said there was no reboot button?  I power-cycled the modem;  with the ac adapter/brick in this and most devices it is a pain.

Tested the stream.  It worked.

That poor cable modem is handling all of our NAT until I find a “real” firewall.  At some point it must have decided to screw up its NAT table.

That’s why we have this $350 power strip, in case our board of directors is reading this.

It works, as you can see in these photos with my work light, a 46W fluorescent from Home Depot.

Light on.

The PDU monitors its power usage.

Light off.

This won’t solve all our problems;  I could still have to come in if the cable modem locks up.  But it will be useful for this, and the other devices that need power-cycling, such as our PBX and our fax modem. 

My only complaint so far is that, like too many management devices that use email, there is no test available on the management web page to configure email.  I’m pretty sure that although I configured email on the device, it is not getting to Exchange.  That’s a common problem with SBS 2008 and needs a custom SMTP connector to fix, which I will remember to get to before I put the PDU in service.

If you’re a small shop, look into Server Technology.  They have devices as small as 2 outlets with the same functionality for about $220.


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