Editing Polarential telegraph system

A '''polarential telegraph system''' is a direct-current [[Telegraphy|telegraph]] system employing polar [[transmission (telecommunications)|transmission]] in one direction and a form of [[differential duplex transmission]] in the other.<ref>{{cite book|title=IEEE Standard Dictionary of Electrical and Electronics Terms|author=Frank Jay|year=1977|pages=501|quote=A direct-current telegraph system employing polar transmission in one direction and a form of differential duplex...|url=https://books.google.com/books?id=U-tSAAAAMAAJ}}</ref> 

Two types of polarential systems, known as types A and B, are in use. In [[half-duplex operation]] of a type A polarential system, the direct-current balance is independent of [[line (electrical engineering)|line]] resistance. In half-duplex operation of a type B polarential system, the direct current is substantially independent of the line leakage. Type A is better for [[Electrical cable|cable]] loops where leakage is negligible but resistance varies with temperature. Type B is considered better for [[open wire]] where variable line leakage is frequent.<ref>{{FS1037C MS188}}</ref>

==See also==

* [[Neutral direct-current telegraph system]]

==References==
{{reflist}}

[[Category:Telegraphy]]