The angle between an incident ray and the normal to a reflecting or refracting surface.

A unit of length equal to 10-10 m.
Note 1: The angstrom is not an SI (International System) unit, and it is not accepted for government use (Fed. Std.376B).
Note 2: The angstrom is, and historically has been, used in the fields of optics, spectroscopy, and microscopy.

Power loss caused by the deviation from optimum angular alignment of the axes of source to waveguide, waveguide to waveguide, or waveguide to detector.
Note 1: The waveguide may be dielectric (an optical fiber) or metallic.
Note 2: Angular misalignment loss does not include lateral offset loss and longitudinal offset loss.

1. automatic number identification.
2. application-to-network interface.

Pertaining to transmission in which the time interval separating any two significant instants in sequential signals is not necessarily related to the time interval separating any other two significant instants.
Note: Isochronous and anisochronous are characteristics, while synchronous and asynchronous are relationships.

See asynchronous transmission.

Pertaining to a material whose electrical or optical properties vary with (a) the direction of propagation of a traveling wave or with (b) different polarizations of a traveling wave.
Note 1: Anisotropy is exhibited by non-cubic crystals, which have different refractive indices for lightwaves propagating in different directions or with different polarizations.
Note 2: Anisotropy may be induced in certain… (Read More →)

Abnormal propagation caused by fluctuations in the properties (such as density and refractive index) of the propagation medium.
Note: AP may result in the reception of signals well beyond the distances usually expected.

A 7- or 10-digit call to the directory number of the public service answering point (PSAP) (where applicable) causing the E911 system (emergency 9-1-1 system) to send to the PSAP a multifrequency (MF) pulse train devoid of the caller's emergency service identification. [T1.414-1998]

The name of a file-transfer protocol that allows a user on one host to access and transfer files to and from another host over a network. [After 2382-pt.35]