Telephone line tone specification

These tones are defined by the local telecommunications regulatory authority; Austel, FCC, etc. There is no one international standards document.

In the USA and Canada, there were so many tones used in so many ways in different types of switching machines that it wasn't realistic to create a Standard for them, so the tones and methods were placed in an Appendix of ANSI T1.401-1993, which has probably been updated a few times by now. An Appendix is used to convey information, but it contains no requirements. ANSI T1.401 is the Standard for the interface between Carriers and their customers for Loop-Start and Ground-Start signaling (basically, think POTS). All of this work was harmonized with Canada's CSA, by our illustrious Chairman, who was Canadian.

Special Information Tones (SIT) and the related messages, is contained in ANSI T1.209.

Don

The ITU used to publish the information in their documents

Alan

-- Sell your surplus electronic components at

None of those agree with the tones used in the US, which are all below 1kHz.

don

Regarding the 2 CCTIT systems I'm familiar with here are the values which should correspond to those in the US

CCTIT No.3 CCTIT No.4 Busy tone 2280Hz +OR- 6Hz 2040Hz,2400Hz, 150+or-30 ms 600ms + OR -120ms 2040+OR-6Hz,

Your comments are not relevant. It's unfortunate you did not observe that the OP was NOT asking about interoffice signaling.

Learn to read. Your comments are not relevant to the subject.

Thats why I indicated that they are CCITT codes which is also known as the International Telecommunications Union.

CCITT = International Telecommunications Union Not only used for international traffic but also for submarine communications, land based cable and microwave links. Ummmm ...You claim? So what do they use now? That is what the Op is asking and no one has given him an answer till I wrote .

It will work just as well as with a multifrquency dial phone if you connect up a 1 to 10 pulse dialling phone there.

I can see you are confusing dialing modes/frequencies with busy tone and ringing frequencies. Now ... CCITT specs give 2 seperate frequencies ranging from 700Hz to

"Go easy with the whisky"

theJackal

WRONG! Try getting a C1 line on a type 2002 channel. You can go upto

"Go easy on the whisky"

theJackal

Oops sorry I missed that. Valuable site and nice information .

"Go easy on the whisky"

theJackal

Watch TV it will educate you more

"If you believe everything you read, better not read." "Go easy on the whisky "

theJackal

ha ha the great instructor has spoken.

Most men are within a finger's breadth of being mad.

Diogenes

"Go easy with the whisky"

theJackal

Those are all "inter-equipment" tones used for long distance signalling. The UK used to use 2280 extensively many years ago while the 2040/2400 tones were used for signalling between countries in Europe.

The UK 2280 system used "decadic" dialling (ie 1 to 10 pulses) for dialling the numbers with various other tone lengths for control signals (ie call answer).

The 2040/2400 system was basically a four bit binary with one tone representin 0 and the other representin 1. The number was sent as a series of four tones. This gave a total of 16 possible combinations some of which were used for control.

Alan

-- Sell your surplus electronic components at

But I already gave the OP a link to :

where there is a pretty comprehensive list of the tones a telephone subscriber would hear, not the tones which are used inter-equipment.

Alan

-- Sell your surplus electronic components at