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+====== LNet current source ======
+[[english|{{  rocrail-logo-35.png}}]]
+[[english|Content]] -> [[hardware-en|Hardware]] -> [[hardware-en#locoio|GCA]]
+  *  [[mgv-overview-en|The GCA modules]]
+ \\
+^^^^By Peter Giling ^^^^
+ \\
+===== current source =====
+\\
+To start with, this current source has NOTHING to do with the power that any LNet unit needs to get working.\\
+Communication in LNet and most LocoNet devices is done via one single wire.\\
+This wire is carrying between 10 and 15 Volts, and will be short circuited to ground when communication is taking place.\\
+Some available products feed this 10-15 V via a simple resistor.\\
+But the original way of achieving this, is to feed this 10-15V via a so called current source.\\
+It is basicly doing the same as a simple resistor, but it limits the current in the short circuit situation \\
+to 15 mAmp maximum.\\
+This will avoid that any wire resistance over the used cable will cause communication flaws.\\
+This of course between certain limits.\\
+There is a technical more important reason to do it this way, but there is no need to go that far in explanation.\\
+A problem could arise, when -for example- GCA85 or GCA101 or CAN_GCLN are connected to the LNet together with any central unit\\
+like Twincenter, Intellibox and/or any of the available Digitrax units.\\
+All these units contain some way of feeding this 15 mA to the LNet communication line.\\
+These currrents are considered to add to each other, so the total current will be much higher than needed.\\
+That is why GCA units all provide the option to shut off this current source.\\
+When GCA85 or GCA101 or CAN_GCLN is the only main LNet unit, its current source should always be activated.\\