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New Gear: Eaton 9130 Dual Conversion UPS

We have a pair of UPSs here; one in the office and another in the house. In both cases, they run the network core; Ethernet switches, Wi-Fi access points, IoT hubs and the like. Our reliance on power-over-ethernet means that there are actually quite a lot of gear that’s on the UPSs.

For many years the UPS in my office was made by Belkin. It was cheap. It did the job, sustaining the network core through many a minor outage. Being fanless, it was silent…which I deeply admire.Eaton 9130 2UHowever, as with most low-cost UPSs, it was “line-interactive” design. In such a design the power provided by the batteries and invertor is connected in parallel to the utility power. When utility power falters the local circuitry tries to make up the slack. The design is simple. Any UPS under $500 new is almost certainly a line-interactive design.

More sensitive gear is better served using a more sophisticated design known as “online” or “dual-conversion.” An online UPS puts its active circuitry between the utility power and the load. The utility power is turned into DC, which feeds the batteries and the invertor, which makes brand new, pristine, stable AC power for the load.

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Amazon Sidewalk Approaches

As a household that has several Amazon Echo devices, I feel obligated to share the news about Amazon Sidewalk, including how to disable it.

What is Sidewalk?

Sidewalk is a “feature” in the latest firmware for the current generation of Amazon smart home products, including; Echo smart speakers, Ring doorbells & security cameras, and Tile trackers. When enabled, Sidewalk capable devices used by neighbors, visitors or passers-by are able to leverage your local internet connectivity.

Amazon says that these Sidewalk interlopers are allowed a limited amount of bandwidth, just 80 kbps, which is about the same as a tradition VoIP phone call.

Why Sidewalk?

That’s simple – ubiquitous connectivity is very convenient. Amazon knows this from years of experience. For example, their WhisperNet was a mechanism leveraging AT&T’s 3G mobile network to provide ubiquitous connectivity to early Kindle e-book readers.

Tile tracker

Imagine someone who uses Tile Pro to track their car keys. They are, as so many do each day, dropping their child off at Travis Elementary School, which is across the street.

It could be very handy if their Tile Pro found our front room Echo Dot, allowed it to ping Amazon servers. If they later lost their car keys, Amazon would know they had been near our home. Presumably, Amazon would have a more detailed record of their location that might otherwise be possible.

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Offline Today

From 3am this morning our home network has been offline. This was expected. Comcast, our primary access provider, was quite good about notifying us of a planned fiber upgrade. The process has been taking areas of the neighborhood offline briefly…

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SOHO Tech: Power-Over-Ethernet is Awesome!

Over the years I’ve come to admire 802.3af standard power-over-Ethernet (aka P.O.E.), even for small- or home-office applications. What follows is an introduction to the topic, and some novel ideas about its use in possibly unexpected applications.

IEEE 802.3af Power-over-Ethernet is the industry standard approach to delivering DC power to network attached devices. Given a P.O.E.-capable switch, or a P.O.E. inserter, DC power is delivered over the same Ethernet connection that provides connectivity. Thus one wire is all that’s required to a distant device on the network.

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