Telephony

[John Fields]

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.

 

[[email protected]]

---
That can be as simple as a resistive voltage divider on the input.

Do you have any information regarding the amplitude of the
call-waiting tone relative to the data signal?

The calling tone is 80 Vrms (more or less 10 Vrms). So 1,41*90 Vpeak =
127Vpeak. And there is the necessity of capacitors to filter the DC
signal when the phone is not being used (about 48Vdc).
About call-waiting tone signal, It is a acoustic signal. I measured
0,2-0,5Vrms but my multimeter isn't true rms.

PH

 

[John Fields]

The calling tone is 80 Vrms (more or less 10 Vrms). So 1,41*90 Vpeak =
127Vpeak. ^^^^^

VRMS

 

[Ryan Weihl]

---
"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.

J F
I followed you mesgs here a little bit.
did a search on google and came up with this one:
http://phonetray.traysoft.com/?gclid=CP_fjLvVoooCFQ4HPwodc0GtvA
question: does this work? do you need a special modem to detect the
tone?
rw

--

 

[[email protected]]

VRMS

I am and my multimeter are very fast. I am joking

My thought: provided that it is a acoustic/audible signal, that has
the same amplitude when I am talking to telephone Or no? hahahaha,
that is, maybe it isn't necessarily true!

Do you know any way to measure it?

PH

 

[[email protected]]

J F
I followed you mesgs here a little bit.
did a search on google and came up with this one:http://phonetray.traysoft.com/?gclid=CP_fjLvVoooCFQ4HPwodc0GtvA
question: does this work? do you need a special modem to detect the
tone?
rw

--

It works really. Read the past messages! You can get the same function
adding the string +PCW=1 if your modem supports call waiting. But we
want to learn to make that. Do you understand? We don't want only to
use the modem

PH

 

[John Fields]

J F
I followed you mesgs here a little bit.
did a search on google and came up with this one:
http://phonetray.traysoft.com/?gclid=CP_fjLvVoooCFQ4HPwodc0GtvA
question: does this work? do you need a special modem to detect the
tone?

 

[[email protected]]

---
Yes, it works. Read some of the OP's posts to that effect.

You need a modem which supports call-waiting detection. The spec is
provided on the web page, I think.

Why is difficult to find those informations?
Google for "+PCW=1 modem v 92" and you will find only few pages.
Why?

Pedro Henrique

 

[[email protected]]

---
Yes, it works. Read some of the OP's posts to that effect.

You need a modem which supports call-waiting detection. The spec is
provided on the web page, I think.

JF,

What do OP mean, please?

PH

 

[Jamie]

Why is difficult to find those informations?
Google for "+PCW=1 modem v 92" and you will find only few pages.
Why?

Pedro Henrique

if you're talking about the AT Hayse commands, I find them easy.
http://www.modem.com/general/extendat.html
http://www.modemsite.com/56k/hcf9.asp
ect..

 

[[email protected]]

if you're talking about the AT Hayse commands, I find them easy.http://www.modem.com/general/extendat.htmlhttp://www.modemsite.com/56k/hcf9.asp
ect..

Only one of them refers to +PCW string. I want to mean that those
informations aren't found easily from modem manufacturers.

PH

 

[John Fields]

JF,

What do OP mean, please?

 

[John Fields]

Why is difficult to find those informations?
Google for "+PCW=1 modem v 92" and you will find only few pages.
Why?