The term "Short Circuit Test Line" denotes an arrangement in an end office which provides for an ac short circuit termination of a trunk or line by means of a capacitor of at least four microfarads.

A general term applied to message toll traffic between nearby points. In common usage, this term is ordinarily applied to message toll traffic between points less than 20 to 50 miles apart. [47CFR]

An event beginning with the occurrence of a bit error ratio (BER) of 10-2 or worse, continuously for each of three or more consecutive seconds, which can last up to 120 seconds. An SIE clears when 10 consecutive seconds pass in which none of them is an SES.
Note: The 10-2 BER continuously over each second implies that all sub-intervals,… (Read More →)

A store-and-forward service in telephony and data systems that allows the exchange of short text messages between end-user devices; the length of the message varies by language up to a maximum of 160 characters in the Latin alphabet. There are gateways from e-mail and Web to SMS, and from SMS to e-mail. The term “SMS” is sometimes also used to… (Read More →)

In optical communication, optical radiation having a wavelength less than approximately 1 m.

In radio communications, pertaining to the band of frequencies approximately between 3 MHz and 30 MHz.
Note: "Shortwave" is not a term officially recognized by the international community.

The noise caused by random fluctuations in the motion of charge carriers in a conductor.
Note: There is often a minor inconsistency in referring to shot noise in an optical system: many authors refer to shot noise loosely when speaking of the mean square shot noise current (amperes2) rather than noise power (watts).

Abbreviation for International System of Units.

1. service access code,
2. special area code.

Either of the two circuits used to derive a phantom circuit.