View source for Simplex signaling

{{Use American English|date=September 2024}}

'''Simplex signaling''' (SX) is [[signaling]] in which two conductors are used for a single [[telecommunication circuit]], and a center-tapped coil, or its equivalent, is used to split the signaling current equally between the two conductors. The return path for the current is [[earth-return telegraph|through ground]]. 

It is distinct from a [[phantom circuit]] in which the return current path for power or signaling is provided through different signal conductors.
SX signaling may be one-way, for intra-central-office use, or the simplex legs may be connected to form full-duplex signaling circuits that function like composite (CX) signaling circuits with [[E and M signaling|E&M]] lead control.

Simplex is also used to describe a powering method where one or more signal conductors carries direct current to power a remote device, which sends its output signal back on the same conductor.  [[Phantom powering]] as used in [[Sound recording and reproduction|audio]] is a form of simplex powering, as the return current flows through the ground or shield conductor.

==References==
*{{FS1037C MS188}}

[[Category:Telephony signals]]


{{telephony-stub}}