Polyphonic ring tone.

Folks,

I need to generate a simple polyphonic ring-tone, say like the one we
have on old POTS telephones. I need to know the frequencies and also
the cadencing information, e.g. 1 second of polyphonic tone followed by
1 second of silence and so on.

Currently I am generating a 1 second of a single frequency tone
followed by 1 second of silence. My boss however wants something more
like a POTS phone ring-tone. Hence this post.

Any help will be appreciated. 

T.

Hello T.,

In the U.S., the ringback heard in the phone is a mix of 440 and 480 Hz, 
both are cadenced together with a cadence of 1 sec on and 3 sec off. The 
actual sound produced by the bell is better produced with a recorded file.

Clay


<tanmay.zargar@gmail.com> wrote in message 
news:1123536395.496721.309050@g49g2000cwa.googlegroups.com...
> Folks,
>
> I need to generate a simple polyphonic ring-tone, say like the one we
> have on old POTS telephones. I need to know the frequencies and also
> the cadencing information, e.g. 1 second of polyphonic tone followed by
> 1 second of silence and so on.
>
> Currently I am generating a 1 second of a single frequency tone
> followed by 1 second of silence. My boss however wants something more
> like a POTS phone ring-tone. Hence this post.
>
> Any help will be appreciated.
>
> T.
> 

tanmay.zargar@gmail.com writes:

> My boss however wants something more like a POTS phone ring-tone.

Touch-tone or rotary dial?
-- 
%  Randy Yates                  % "Watching all the days go by...    
%% Fuquay-Varina, NC            %  Who are you and who am I?"
%%% 919-577-9882                % 'Mission (A World Record)', 
%%%% <yates@ieee.org>           % *A New World Record*, ELO
http://home.earthlink.net/~yatescr

Do you know the dB/dBm0 levels for each of the frequencies?

<tanmay.zargar@gmail.com> wrote in message 
news:1123543425.660042.31780@g44g2000cwa.googlegroups.com...
> Do you know the dB/dBm0 levels for each of the frequencies?
>

 I'm sure there is a spec. I don't recall an exact level being needed, but 
typically something in the neighborhood of -6 to -10 dBm was common in use. 
And both frequency components have the same amplitude.

Clay

Clay S. Turner wrote:
> Hello T.,
> 
> In the U.S., the ringback heard in the phone is a mix of 440 and 480 Hz, 
> both are cadenced together with a cadence of 1 sec on and 3 sec off. The 
> actual sound produced by the bell is better produced with a recorded file.

The repetition of the bell clangs is typically 20 Hz.

Jerry
-- 
Engineering is the art of making what you want from things you can get.
�����������������������������������������������������������������������

tanmay.zargar@gmail.com wrote:
> Folks,
> 
> I need to generate a simple polyphonic ring-tone, say like the one we
> have on old POTS telephones. I need to know the frequencies and also
> the cadencing information, e.g. 1 second of polyphonic tone followed by
> 1 second of silence and so on.
> 
> Currently I am generating a 1 second of a single frequency tone
> followed by 1 second of silence. My boss however wants something more
> like a POTS phone ring-tone. Hence this post.
> 

Clay already gave you info on the ringback tone (i.e., ring on the far 
end), but it was not clear to me if you wanted that or ring you hear 
when someone calls you (ring on the near end).

If the latter, the U.S. cadence is 2 seconds on, 4 seconds off.  As 
Jerry pointed out, it's 20Hz.  Not only that, but IIRC, it's also 90V. 
It was originally implemented in such a way as to move a physical 
clapper against a physical bell.  We surely don't need 90V/20Hz to 
generate a ring these days, but that's what the standard is.  Well - at 
least for land lines.

-- 
Jim Thomas            Principal Applications Engineer  Bittware, Inc
jthomas@bittware.com  http://www.bittware.com    (603) 226-0404 x536
Being a good example is hard.  I'm trying to serve as a horrible
warning instead. - Brian Crane

Jim,

I actually needed the ringing tone (or alerting tone) and NOT the
ringback tone (as heard by the far end talker). Thanks for pointing
that out. I think I should have made that clearer.

Anyhow, I need to generate that ringing tone for a wireless handset
(not a landline phone). You mentioned that it is a single monophonic
tone at 20Hz. I am not sure if that is what I want. I want (or rather
my boss wants) the standard TRING-TRING (I am feeling really silly
writing this) tone. Now I wish to know what frequencies go into
generating that. I have written a tone cadencer that mixes several
tones to generate a polyphonic tone at a particular sampling frequency.
All I need now, is to know the frequencies and their levels to mix and
get this tone. 

T.

tanmay.zargar@gmail.com wrote:

> Jim,
> 
> I actually needed the ringing tone (or alerting tone) and NOT the
> ringback tone (as heard by the far end talker). Thanks for pointing
> that out. I think I should have made that clearer.
> 
> Anyhow, I need to generate that ringing tone for a wireless handset
> (not a landline phone). You mentioned that it is a single monophonic
> tone at 20Hz. I am not sure if that is what I want. I want (or rather
> my boss wants) the standard TRING-TRING (I am feeling really silly
> writing this) tone. Now I wish to know what frequencies go into
> generating that. I have written a tone cadencer that mixes several
> tones to generate a polyphonic tone at a particular sampling frequency.
> All I need now, is to know the frequencies and their levels to mix and
> get this tone. 
> 
> T.
> 
AFAIK there is no "standard" to the sound the phone must make.  The POTS 
standard calls for a 20Hz 96V waveform on the line, with enough current 
behind it to bang a clapper against a couple of bells in several phones. 
  The POTS standard does _not_ call out what the phone is supposed to do 
with it -- it can ring a bell, make the cheesy fake bell tone you hear 
these days, light a light, shock a dog so you hear agonized bark-yelps, 
whatever.

So what you want is the common tone that everyone uses -- do you want it 
to sound like a modern electronic phone, or do you want it to sound like 
like phones from the '20s to the '70s?  In the former case there's 
probably only two or three tones in there, similar to the ringback tone, 
in the latter case (as someone mentioned before) you should probably 
record one ring cycle and play it back over and over.

-- 

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

tanmay.zargar@gmail.com wrote:

   ...

> Anyhow, I need to generate that ringing tone for a wireless handset
> (not a landline phone). You mentioned that it is a single monophonic
> tone at 20Hz. I am not sure if that is what I want.

It's not. You missed the point.

>                                                I want (or rather
> my boss wants) the standard TRING-TRING (I am feeling really silly
> writing this) tone. Now I wish to know what frequencies go into
> generating that. I have written a tone cadencer that mixes several
> tones to generate a polyphonic tone at a particular sampling frequency.
> All I need now, is to know the frequencies and their levels to mix and
> get this tone. 

The TRING-TRING is produced by (or is an imitation of) two bells, one 
tuned to 440 Hz, the other to 480 Hz. The bells are struck alternately 
by a clapper that is driven at approximately 20 Hz (produced originally 
bu a hand-cranked generator). The bells have high enough Q so that their 
decay in the 50 ms between strikes is probably negligible, but clapper's 
asynchronous striking may have a minor effect on the timbre. I clocked 
my phone's ring as a 25% duty cycle in a 4-second period.

The canonic bells are approximate hemispheres. You might use a bicycle 
bell to sample the appropriate harmonic content. If you have an old desk 
set with a mechanical ringer, operate the ringer at 90 V, 20 Hz or ding 
a bell with a metal tool while sampling with a microphone.

Jerry
-- 
Engineering is the art of making what you want from things you can get.
�����������������������������������������������������������������������