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Old 3rd Sep 2011, 9:20 pm   #19
AndiiT
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Join Date: Aug 2005
Location: Saltburn-East, Cleveland, UK.
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Default Re: Does your telecom provider support pulse dialling?

Quote:
Originally Posted by OscarFoxtrot View Post
Telephone lines have to sense loop disconnection
Having given this statement some thought, the above is quite correct as the very action of taking the telephone "off hook" creates a loop, which the equipment recognises as the instruction that the user requires a circuit for use.

If the equipment could not sense the presence/absence of a loop you wouldn't even get as far as having dial tone returned let alone be able use pulse dialling.

Most (probably all) VOIP ATAs will only accept Tone dialling but the way that they present dial tone to the telephone differs from that of a conventional telephone exchange in that the ATA isn't relying on a loop being generated in order to present dial tone to the telephone.

Incidentally dial tone isn't actually required, it is provided as a "confidence tone" to indicate to the user that the equipment at the exchange is ready and awaiting further instruction, such as a pulse or tone digit train; for example you don't receive dial tone when making a mobile call and the call is still connected; mobile calls still have to be routed through a telecoms switch (exchange) at some point in their journey.

Regards
Andrew
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