"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:
“Honest men are the soft easy cushions on which knaves Repose and fatten.”
—Thomas Otway (1652–1685)
“A man is reputed to have thought and eloquence; he cannot, for all that, say a word to his cousin or his uncle. They accuse his silence with as much reason as they would blame the insignificance of a dial in the shade. In the sun it will mark the hour. Among those who enjoy his thought, he will regain his tongue.”
—Ralph Waldo Emerson (1803–1882)
“There sighs, lamentations and loud wailings resounded through the starless air, so that at first it made me weep; strange tongues, horrible language, words of pain, tones of anger, voices loud and hoarse, and with these the sound of hands, made a tumult which is whirling through that air forever dark, as sand eddies in a whirlwind.”
—Dante Alighieri (1265–1321)