Telephony

[[email protected]]

Hello,

I would like to develop a circuit to disconnect a dial-up connection
when I receive the signal of a call in waiting. Could someone speak me
where I could get the specifications of public telephony [in US if
there is not a world-wide standard]?

Thanks you,
Pedro Henrique

 

[Homer J Simpson]

I would like to develop a circuit to disconnect a dial-up connection
when I receive the signal of a call in waiting. Could someone speak me
where I could get the specifications of public telephony [in US if
there is not a world-wide standard]?

http://www.pagoo.com/

 

[[email protected]]

Homer J Simpson escreveu:

I would like to develop a circuit to disconnect a dial-up connection
when I receive the signal of a call in waiting. Could someone speak me
where I could get the specifications of public telephony [in US if
there is not a world-wide standard]?

http://www.pagoo.com/

I live in Brazil, so I would like a circuit connected to my telephone
line to disconnect my dial-up connection.
I would like to get the fixed telephony world-wide standards.

thanks you,
PH

 

[Homer J Simpson]

I live in Brazil, so I would like a circuit connected to my telephone
line to disconnect my dial-up connection.
I would like to get the fixed telephony world-wide standards.

Is that legal in Brazil? Do you have call waiting?

 

[John Fields]

Homer J Simpson escreveu:

I would like to develop a circuit to disconnect a dial-up connection
when I receive the signal of a call in waiting. Could someone speak me
where I could get the specifications of public telephony [in US if
there is not a world-wide standard]?

http://www.pagoo.com/

I live in Brazil, so I would like a circuit connected to my telephone
line to disconnect my dial-up connection.
I would like to get the fixed telephony world-wide standards.

 

[[email protected]]

Is that legal in Brazil? Do you have call waiting?

Yes, I have the service.

 

[[email protected]]

Yes, I have the service.

Forgive me:

Yes, I have the call waiting service installed.
I think it is legal in Brazil. It isn't a problem anyway Isn't
legal in US?

 

[[email protected]]

Homer J Simpson escreveu:

I would like to develop a circuit to disconnect a dial-up connection
when I receive the signal of a call in waiting. Could someone speak me
where I could get the specifications of public telephony [in US if
there is not a world-wide standard]?
http://www.pagoo.com/

I live in Brazil, so I would like a circuit connected to my telephone
line to disconnect my dial-up connection.
I would like to get the fixed telephony world-wide standards.

They are alike, I believe.
I would like to read the US and europe standards to get some ideas.
I could not to get the brazilian standards yet. Only for mobile
communication :-(

And what about the circuit? Do you think it possible?

thanks you,
PH

 

[John Fields]

Homer J Simpson escreveu:

news:[email protected]...

I would like to develop a circuit to disconnect a dial-up connection
when I receive the signal of a call in waiting. Could someone speak me
where I could get the specifications of public telephony [in US if
there is not a world-wide standard]?

http://www.pagoo.com/

I live in Brazil, so I would like a circuit connected to my telephone
line to disconnect my dial-up connection.
I would like to get the fixed telephony world-wide standards.

They are alike, I believe.
I would like to read the US and europe standards to get some ideas.
I could not to get the brazilian standards yet. Only for mobile
communication :-(

And what about the circuit? Do you think it possible?

---
It may not be necessary if you can configure your modem to
disconnect on call waiting:

http://www.modemsite.com/56k/v92.asp

here's a link to get you started:

http://en.wikipedia.org/wiki/Call_waiting

with much more available at:

http://www.google.com/search?source...&rls=GFRC,GFRC:2006-50,GFRC:en&q=Call+waiting

 

[[email protected]]

On 6 Feb 2007 16:25:28 -0800, "[email protected]"
Homer J Simpson escreveu:

I would like to develop a circuit to disconnect a dial-up connection
when I receive the signal of a call in waiting. Could someone speak me
where I could get the specifications of public telephony [in US if
there is not a world-wide standard]?
http://www.pagoo.com/
I live in Brazil, so I would like a circuit connected to my telephone
line to disconnect my dial-up connection.
I would like to get the fixed telephony world-wide standards.

They are alike, I believe.
I would like to read the US and europe standards to get some ideas.
I could not to get the brazilian standards yet. Only for mobile
communication :-(

And what about the circuit? Do you think it possible?

---
It may not be necessary if you can configure your modem to
disconnect on call waiting:

http://www.modemsite.com/56k/v92.asp

here's a link to get you started:

http://en.wikipedia.org/wiki/Call_waiting

with much more available at:

http://www.google.com/search?sourceid=navclient&aq=t&ie=UTF-8&rls=GFR...

Thanks you by the links but I would like to make a circuit to detect
the call waiting tone and disconnect my dial-up automatically
[answering the call waiting tone with the FLASH + 1 in Brazil to
accept the incoming call and disconnect the current call] independent
if my modem and my telephone company supports v.92.

regards,
Pedro Henrique

 

[John Fields]

Thanks you by the links but I would like to make a circuit to detect
the call waiting tone and disconnect my dial-up automatically
[answering the call waiting tone with the FLASH + 1 in Brazil to
accept the incoming call and disconnect the current call] independent
if my modem and my telephone company supports v.92.

---
From:
http://www.voip-info.org/wiki/view/Asterisk+indications+Brazil

It appears your call waiting standard is:

call waiting = 425/50,0/1000,

which means 425Hz for 50 milliseconds followed by 0Hz for 1000
milliseconds.

That means you'll need to detect the 425Hz tone for long enough to
determine whether it's valid or not and then detect the absence of
that tone for 1 second in the presence of your data signal. You may
want to do that two or three times just to make sure it's really the
call-waiting signal, then generate the FLASH +1 signal to disconnect
the modem and transfer the call to the phone.

 

[[email protected]]

Thanks you by the links but I would like to make a circuit to detect
the call waiting tone and disconnect my dial-up automatically
[answering the call waiting tone with the FLASH + 1 in Brazil to
accept the incoming call and disconnect the current call] independent
if my modem and my telephone company supports v.92.

---
From:http://www.voip-info.org/wiki/view/Asterisk+indications+Brazil

It appears your call waiting standard is:

call waiting = 425/50,0/1000,

which means 425Hz for 50 milliseconds followed by 0Hz for 1000
milliseconds.

That means you'll need to detect the 425Hz tone for long enough to
determine whether it's valid or not and then detect the absence of
that tone for 1 second in the presence of your data signal. You may
want to do that two or three times just to make sure it's really the
call-waiting signal, then generate the FLASH +1 signal to disconnect
the modem and transfer the call to the phone.

Very thanks by informations.
Only Today I could read in a book today that in Brazil these
informations:

425 Hz during 60 ms ± 10%
0 Hz during 250 ms ± 10%

JF,

I was thinking in a simpler solution: to install a 425 Hz filter in my
phone and connect to a loudspeaker. So I will be able to hear the
signal and go to telephone to press FLASH and 1. What do you think?
There is a telephone connected to modem, so it will not be a
discomfort to me.
Could you give me a suggestion to the filter?

thanks you!,
PH

 

[John Fields]

Thanks you by the links but I would like to make a circuit to detect
the call waiting tone and disconnect my dial-up automatically
[answering the call waiting tone with the FLASH + 1 in Brazil to
accept the incoming call and disconnect the current call] independent
if my modem and my telephone company supports v.92.

---
From:http://www.voip-info.org/wiki/view/Asterisk+indications+Brazil

It appears your call waiting standard is:

call waiting = 425/50,0/1000,

which means 425Hz for 50 milliseconds followed by 0Hz for 1000
milliseconds.

That means you'll need to detect the 425Hz tone for long enough to
determine whether it's valid or not and then detect the absence of
that tone for 1 second in the presence of your data signal. You may
want to do that two or three times just to make sure it's really the
call-waiting signal, then generate the FLASH +1 signal to disconnect
the modem and transfer the call to the phone.

Very thanks by informations.
Only Today I could read in a book today that in Brazil these
informations:

425 Hz during 60 ms ± 10%
0 Hz during 250 ms ± 10%

JF,

I was thinking in a simpler solution: to install a 425 Hz filter in my
phone and connect to a loudspeaker. So I will be able to hear the
signal and go to telephone to press FLASH and 1. What do you think?
There is a telephone connected to modem, so it will not be a
discomfort to me.
Could you give me a suggestion to the filter?

---
Yes. I think the right filter would be basically a squelch that
would use an averaging detector for the data and then use the
filtered 425Hz rising above that level to open up a gate and let the
425Hz through. Either that or use the 425Hz signal to turn on a
beeper, momentarily, to let you know that someone was trying to call
you. That might be the better way because it would get rid of the
annoying squelch tails.


Or, maybe, something like this:

http://phonetray.traysoft.com/?gclid=CMDFg_fGnYoCFQgTWAodkTi2nA

If it'll work with your modem.

You can download it for free to find out, anyway.

I'm interested in the filter, so I'll work up something tomorrow and
post it probably on Friday, unless something unexpected comes up.

 

[[email protected]]

---
Yes. I think the right filter would be basically a squelch that
would use an averaging detector for the data and then use the
filtered 425Hz rising above that level to open up a gate and let the
425Hz through. Either that or use the 425Hz signal to turn on a
beeper, momentarily, to let you know that someone was trying to call
you. That might be the better way because it would get rid of the
annoying squelch tails.

Or, maybe, something like this:

http://phonetray.traysoft.com/?gclid=CMDFg_fGnYoCFQgTWAodkTi2nA

If it'll work with your modem.

You can download it for free to find out, anyway.

I'm interested in the filter, so I'll work up something tomorrow and
post it probably on Friday, unless something unexpected comes up.

I don't believe, that softwares works! Very very thanks, JF!

Anyway, I am also very interested in others solutions like a filter/
loudspeaker or better, a digital circuit with a LM567. This CI isn't
very expensive.

Very thanks,
Pedro Henrique

 

[[email protected]]

I don't believe, that softwares works! Very very thanks, JF!

Anyway, I am also very interested in others solutions like a filter/
loudspeaker or better, a digital circuit with a LM567. This CI isn't
very expensive.

Very thanks,
Pedro Henrique

The secret of that software is only to add string modem "+PCW=0" or
"+PCW=1", no?

---- Portuguese - Brazil - for documentation
Para se desconectar uma conexão dial-up ativa automaticamente quando
há alguém tentando chamar o respectivo número telefônico, adicione a
string +PCW=1 ao modem. É claro, o serviço Chamada em espera deve
estar ativo na linha telefônica.

 

[John Fields]

The secret of that software is only to add string modem "+PCW=0" or
"+PCW=1", no?

 

[[email protected]]

I tried and it has worked.

PH

 

[John Fields]

Anyway, I am also very interested in others solutions like a filter/
loudspeaker or better, a digital circuit with a LM567. This CI isn't
very expensive.

---
"Integrated Circuit" (IC), no?

Good thought.

Since your call-waiting tone is 425Hz, one cycle takes:

1
t = ------- = 0.00235 seconds
425Hz

to complete, and since the tone will be on for 60 milliseconds, the
number of cycles during that time will be:

60ms
n = --------- = 25.53 ~ 25
2.35ms

Looking at the data sheet for the 567:

http://www.datasheetcatalog.com/datasheets_pdf/N/E/5/6/NE567.shtml

on page 5 (407) there are two graphs which show frequency VS
bandwidth and greatest number of cycles needed for output. Since
you have 25 cycles available it looks like if you set your bandwidth
for something between 10 and 14% it might work. I don't know what
effect the data signal is going to have on the 425Hz tone other that
it'll degrade its detection, so the best thing might be to just
wire one up and see what you can do with it.

 

[John Fields]

I tried and it has worked.

---
Excellent!

So now you don't need the filter?

No matter, I'm intrigued so I'll work something up and post what I
find when I'm done.

 

[[email protected]]

---
Excellent!

So now you don't need the filter?

No matter, I'm intrigued so I'll work something up and post what I
find when I'm done.

Well, I don't need the filter, but I don't have nothing to do and I'm
intrigued too .

I am plus interesed in tone decoder. The problem is that input to
LM567 is at most 200mVrms, so I will need to make a reliable
conversion and protection for the CI.

PH