"Soft" Dial Tones
A "soft" dial tone, less often called "secondary" dial tone or "express" dial tone, is audibly the same as a regular one, except that there is no actual service active on the line, and normal calls cannot be made. It is maintained only so that an attached phone can dial the emergency telephone number (such as 9-1-1, 1-1-2 or 9-9-9), in compliance with the law in most places. It can sometimes call the business office of the local exchange carrier which owns or last leased the line, such as via 6-1-1. Other functions such as ringback or ANAC may also be accessed by technicians in order to facilitate installation or activation.
Often, a new telephone number is assigned to the line so that it can function, but callback is restricted, and end-users do not know the number. These numbers may be outside the normal range used for regular lines, potentially causing trouble when telephone numbering plans are changed.
Deactivated lines can also be maintained with no dial tone at all, while still connected to and powered by the switch, in a state sometimes called INB or Installation Busy.
Read more about this topic: Dial Tone
Famous quotes containing the words soft, dial and/or tones:
“Here they are. The soft eyes open.
If they have lived in a wood
It is a wood.
If they have lived on plains
It is grass rolling
Under their feet forever.”
—James Dickey (b. 1923)
“The television screen, so unlike the movie screen, sharply reduced human beings, revealed them as small, trivial, flat, in two banal dimensions, drained of color. Wasn’t there something reassuring about it!—that human beings were in fact merely images of a kind registered in one another’s eyes and brains, phenomena composed of microscopic flickering dots like atoms. They were atoms—nothing more. A quick switch of the dial and they disappeared and who could lament the loss?”
—Joyce Carol Oates (b. 1938)
“‘Tis not that thy mien is stately,
‘Tis not that thy tones are soft;”
—Charles Stuart Calverley (1831–1884)