A direct-current telegraph system employing polar transmission in one direction and a form of differential duplex transmission in the other.
Note: 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 resistance. In half-duplex operation of a type B polarential… (Read More →)

Of an electromagnetic wave, the property that describes the orientation, i.e., time-varying direction and amplitude, of the electric field vector.
Note 1: States of polarization are described in terms of the figures traced as a function of time by the projection of the extremity of a representation of the electric vector onto a fixed plane in space, which plane is… (Read More →)

Diversity transmission and reception wherein the same information signal is transmitted and received simultaneously on orthogonally polarized waves with fade-independent propagation characteristics

An optical fiber in which the polarization planes of lightwaves launched into the fiber are maintained during propagation with little or no cross-coupling of optical power between the polarization modes. [2196]
Note 1: Cross sections of polarization-maintaining optical fibers range from elliptical to rectangular.
Note 2: Polarization-maintaining optical fibers are used in special applications, such as in fiber optic sensing… (Read More →)

Synonym polarization-maintaining optical fiber.

See: Security Policy [7498-2].

A set of logical functions and physical components that enable the optimal operation and management of network resources, and allows consistent behavior for a variety of services, across a range of access technologies based on an individual customer's requirements. Policy Management provides policy control, resource allocation and management, and admission control functions based on pre-defined policy rules that can be… (Read More →)

1. Network control in which the control station invites tributary stations to transmit in the sequence specified by the control station.
2. In point-to-point or multipoint communication, the process whereby stations are invited one at a time to transmit.
3. Sequential interrogation of devices for various purposes, such as avoiding contention, determining operational status, or determining readiness to send or… (Read More →)

In cryptography, the existence of a cryptographic key in more than one secure physical location. [After X9.49]

Synonym plastic-clad silica fiber.