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--- glossary:glossary_a [2019/09/05 22:27] – [AWG] more detail and ideas of what to expect tgerbic
+++ glossary:glossary_a [2019/09/09 22:01] – [Address] Add some useful context to Address. tgerbic
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-Alternating Current - Generally with a sinusoidal wave form. Mains power in Britain and Europe is 230v AC at 50Hz, that is 50 complete cycles per second. USA uses 115v at 60Hz.\\
+Alternating Current. Refers to a situation where current flows back and forth through a conductor (wire) in alternating directions. Generally, the voltage being applied to the conductor has a changing (alternating) polarity so the current has to change direction related to which end of the wire is positive or negative at a given point of time. In most cases we encounter, the voltage moves in a sinusoidal wave shape centered at zero volts, though it could be centered at another point. If it is centered at another point than zero volts, it is most often referred to as having a voltage offset. An AC voltage could have another wave shape besides sinusoidal depending on the application or components it is reacting with. The rate at which it changes direction is referred to as its frequency.
+The opposite of AC is DC where the current only flows in one direction. DC will have a voltage level in only one direction, either positive or negative, referenced to a common, ground or zero volts reference point.
+Mains power in many countries such as Britain, Australia and Europe is at 230v AC at a frequency of 50Hz, that is 50 complete cycles per second. North America uses 115v at 60Hz.
+\\
 [[http://www.allaboutcircuits.com/vol_2/chpt_1/1.html|http://www.allaboutcircuits.com/vol_2/chpt_1/1.html]]
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-**[[glossary:glossary_d#dcc|DCC]]** decoders are used to control trackside accessories such as turnouts and signals using the NMRA standard pulsed signal. The signal can be carried by the track and track feeders or can be a separate circuit, which avoids the risk of a derailment or short preventing the control of the turnouts. All DCC manufacturers make accessory decoders and MERG provide kits.\\
+**[[glossary:glossary_d#dcc|DCC]]** decoders are used to control trackside accessories such as turnouts and signals using the NMRA standard pulsed signal. The accessory decoder is controlled similar to a train decoder using a unique decoder address and a series of function variables. The signal can be carried by the track and track feeders or can be a separate circuit, which avoids the risk of a derailment or short preventing the control of the turnouts.  All DCC manufacturers make accessory decoders and MERG provide kits.\\
 https://www.merg.org.uk/merg_resources/dcc.php
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-The MERG DCC accessory encoder is designed to operate as a DCC command station independently from the track DCC although it uses the NMRA Standard for its information encoding and can operate most other accessory decoders as well as the MERG kits.\\
+The MERG DCC accessory encoder is designed to operate as a DCC command station independently from the track DCC. It uses the NMRA Standard for its information encoding and can operate most other accessory decoders as well as the MERG kits.\\
 https://www.merg.org.uk/merg_resources/dcc.php
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 Address is the unique identification of anything. In the context of DCC it means the coding of each loco or other decoder, which ensures that it identifies the signals intended for it.
+You will encounter two address ranges in the NMRI DCC standard, two-digit addressing (called short addressing) and four-digit addressing (called long or extended addressing). The number of digits refers to how many hexadecimal digits are transmitted/received for a decoder address from the DCC system. A two-digit address can have hex numbers between 01 and FF (1 to 127 decimal). A four-digit address can have from 0001 to 27FF (1 to 10239 decimal). Many model railroad users use four-digit addressing in order to match up the DCC address with the four-digit train engine number to make it easy to remember the number to control the engine.  So, if the engine number is 1234, the train decoder will be set to 1234 as well. Generally address 00 is reserved in each number system for analogue operation and is also known as the Broadcast Address.
+DCC decoders store the addresses in Configuration Variables (CVs). Each decoder vendor may have different set of CVs to store the digits. Refer to the docs that came with your decoder.
 ===== Agile =====
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-===== Auto reverse =====
+===== AT-Bus =====
+An alternative CAN Bus protocol devised by MERG member Roger Edwards which overcomes what he sees as deficiencies in the [[glossary:glossary_c#cbus|CBUS]] protocol.
+===== Auto Reverse Module =====