DCC controlled Hornby turntable using Rail master

[Fishmanoz]

In digital communications, data is composed of short-duration pulses called bit s (binary digits). There are two possible states for each bit: logic 0 (also called low) and logic 1 (also called high). In a closed circuit, these logic elements are represented

 

by direct current voltages. A high-speed data signal varies rapidly between the low and high states. Common values are approximately +0.5 volts for low and +5 volts for high. In some cases different values are used, for example, -3 volts for low and +3 volts

 

for high, or -5 volts for low and -0.5 volts for high. If both voltages have the same polarity, the signal is called unipolar; if the voltages have opposite polarity, the signal is called bipolar.

 

Definition of Polarity in part from http://whatis.techtarget.com/definition/polarity.

 

Clearly polarity is not considered DC from this, rather it starts from whether a voltage is positive or negative.

[Blackbird]

An interesting thesis, of which I am aware, and don't disagree with, but the terminolgy can't be applied to the two rails in a DCC system. Unlke a DC system, when the rails are either +ve or -ve, and are only changed when the controller is reversed. It

 

is the identity of the rail not it's polarity that has to be defined to identify a cross connection which will be a short ciruit, AC or DC.

[Fishmanoz]

Ok Blackbird, not worth continuing, let's agree to disagree. Much of what we are saying is the same anyway I think.