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MA: physical structure blurb

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jaseg 2020-05-20 12:45:17 +02:00
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@ -460,7 +460,31 @@ transport encryption and other cryptographic services\cite{bsi-tr-03109-2,bsi-tr
% FIXME compare to other places where things are not as nice
\subsection{Physical structure and installation}
% FIXME
Smart meters are installed like traditional electricity meters. In Japan this means they are usually installed on an
exterior wall and need to be resistant against weather and extreme environmental conditions (direct sunlight, high
temperature, high humidity). In Germany the meter is always installed either indoors or in an outdoor utility closet
that is sealed to keep out the weather. In most countries the meter is connected through large integrated screw
terminals. In the US meters compliant with the domestic ANSI C12 standard are round and plug into a large socket that is
wired into the house or apartment's electrical connection.
Modern smart meters are usually made with plastic cases. Ferraris meters often used cases stamped from sheet metal with
glass windows on them. Smart meters now look much more like other modern electronic devices. A common construction style
is to separate the case in a front and back half with both halves clipped or ultrasonically welded together. Ultrasonic
welding gives a robust, airtight interface. This interface cannot easily be separated and re-connected without leaving
visible traces, which helps with tamper evidence properties. As an industry-standard process common in various consumer
goods ultrasonic welding is a cheap and accessible technology\cite{easymeter01,ifixit01}.
Communication interfaces sometimes are brought out through regular electromechanical connectors but often also are
optical interfaces. A popular style here is to use a regular UART connected to an LED/phototransistor optocoupler
mounted on the side of the case. The user interface is usually limited to an LCD display. For cost and ingress
protection smart meters rarely use mechanical buttons. Some smart meters use a phototransistor mounted behind the
faceplate that can be activated with a flashlight as a crude contact-less input device\cite{easymeter01}.
All meters provide several options for security seals to be installed to detect opening of the meter or access to its
terminal block. The shape and type of these security seals varies. Factory-installed seals are used to detect tampering
of the meter itself while seals made by the utility during meter installation are used to guard the meter's terminal
block and detect attempts at by-passing.
\section{Regulatory frameworks around the world}
@ -487,7 +511,7 @@ Germany standardized smart metering on a national level. Apart from the calibrat
meter smart meters are covered by a set of communications and security standards developed by the German Federal Office
for Information Security (BSI). Germany mandates smart meter installations for newly constructed buildings and during
major renovations but does not require most legacy residential installations to be upgraded. This is a consequence of a
2013 cost-benefit analysis that found these upgrades to be uneconomical for the vast majority of residential
2013 cost-benefit analysis that found these upgrades to be uneconomical for the majority of residential
customers\cite{bmwi03,bmwi1,bmwe01,brown01}.
The German standards strictly separate between metering and communication functions. Both are split into separate