Phone in use circuit not working

[ehsjr]

On 2/28/2013 2:22 PM, steve wrote:

I tested and built the following circuit.

http://www.circuitstoday.com/telephone-in-use-indicator

It all worked fine untill I tried to test it by calling into my phone.
(the one test I didnt do before I soldered it all together)

What happens is taht the phone rings for a about 1/2 a ring then stops ringing.
To my surprise when I life the phone up the line is alive eg. Its like the device has answered the phone.

I think that the circuit must be drawing too much power and then telling the phone that it has been answered, because the voltage has gone down.

I have had to replace the Transistors with NTE199, which according to the book are the same. I have also used a rectifier that is a 2 amp 400v SIP 2KBP04M-1.
Im wondering if I used a different rectifier if that would change the results?

I recognize that your not suppse to take power from the phone co. but I would like to get this circuit working. Can anyone tell me why its not working.
thanks.

There's a lot wrong with that circuit, but as an experiment
add a small (10uf or less) electrolytic from the base of
Q2 to ground, then ring your phone to see if it works.

Then, when you've got it working or not, remove it from the
phone line and use the parts for something else. It is not
"phone company friendly" nor are the parts properly V rated.

Ed

 

[Jon Kirwan]

On Sat, 2 Mar 2013 21:22:37 -0000, "Ian Field"
<gangprobing.alien@ntlworld.com> wrote:

"Jon Kirwan" <jonk@infinitefactors.org> wrote in message
news:7sm4j81hs4ep7gti49mukuolcvv68unerc@4ax.com...
On Thu, 28 Feb 2013 11:22:00 -0800 (PST), steve
stevesemple@lycos.com> wrote:

I tested and built the following circuit.

http://www.circuitstoday.com/telephone-in-use-indicator

It all worked fine untill I tried to test it by calling into
my phone. (the one test I didnt do before I soldered it all
together)

What happens is taht the phone rings for a about 1/2 a ring
then stops ringing. To my surprise when I life the phone up
the line is alive eg. Its like the device has answered the
phone.

I think that the circuit must be drawing too much power and
then telling the phone that it has been answered, because
the voltage has gone down.

I have had to replace the Transistors with NTE199, which
according to the book are the same. I have also used a
rectifier that is a 2 amp 400v SIP 2KBP04M-1.

Im wondering if I used a different rectifier if that would
change the results?

I recognize that your not suppse to take power from the
phone co. but I would like to get this circuit working. Can
anyone tell me why its not working.

thanks.

There is quite a long specification for telephone lines in
the US. I have a copy, thanks to Don Bowey, when he dropped a
copy over at my home back around 2003 or so. It represents an
industry composite of various systems and includes envelopes
of operation. The gist of it is, as Don wrote before coming
over back then,

"The FCC R&R require a minimum of 5M of customer premises
equipment loop resistance in the on-hook state. Also.
at 220uA some Central Offices will declare a line fault
and remove the line from service."

The basic idea of presenting 5MOhm total customer premises
load (that is the TOTAL of all phones and connected
equipment) when on-hook is incredibly hard to meet with an
unpowered attachment that shows "in use" and "not in use" led
lights.

I've also read that, "if you are in USA or canada Bellcore
specs allow a max of 5micro amps at 48VDC in an on-hook
state." That's 10MOhm, in effect, though I believe the 5MOhm
for the entire premises still fits the spec.

The upshot here is that you aren't going to be seeing an LED
lit continuously and still meet on-hook specifications. You
can design a system to blink periodically,

If you can use that 48V to charge a capacitor above 32V without violating
the on hook current spec; you can make an LED flash very brightly
periodically by dumping the cap into it with a DB3 diac.

You'd have to trial & error for how many uF to make the flash bright enough
without blowing the LED.

Yeah, that is true enough I suppose. So examine:

http://www.infinitefactors.org/misc/spice/Pulser%202.png

That should keep the draw under 1 microamp, while pulsing an
LED for about 10 microsecond pulses. I didn't include a
resistor limiter in series with the LED, as that is something
for the end user to insert as appropriate. I also didn't add
a bridge rectifier, either. Again... up to the user. I don't
think that circuit will do much at 10-12V or less for the off
hook voltages. But if it does, it will blink ... very slowly,
I think.

Jon

 

[Michael A. Terrell]

ehsjr wrote:

On 2/28/2013 2:22 PM, steve wrote:
I tested and built the following circuit.

http://www.circuitstoday.com/telephone-in-use-indicator

It all worked fine untill I tried to test it by calling into my phone.
(the one test I didnt do before I soldered it all together)

What happens is taht the phone rings for a about 1/2 a ring then stops ringing.
To my surprise when I life the phone up the line is alive eg. Its like the device has answered the phone.

I think that the circuit must be drawing too much power and then telling the phone that it has been answered, because the voltage has gone down.

I have had to replace the Transistors with NTE199, which according to the book are the same. I have also used a rectifier that is a 2 amp 400v SIP 2KBP04M-1.
Im wondering if I used a different rectifier if that would change the results?

I recognize that your not suppse to take power from the phone co. but I would like to get this circuit working. Can anyone tell me why its not working.
thanks.


There's a lot wrong with that circuit, but as an experiment
add a small (10uf or less) electrolytic from the base of
Q2 to ground, then ring your phone to see if it works.

Then, when you've got it working or not, remove it from the
phone line and use the parts for something else. It is not
"phone company friendly" nor are the parts properly V rated.

Old 400E KTU cards (1A2 key phone systems) are floating around
surplus and are made for the phone companies.

 

[Michael Black]

On Sat, 2 Mar 2013, Michael A. Terrell wrote:

ehsjr wrote:

On 2/28/2013 2:22 PM, steve wrote:
I tested and built the following circuit.

http://www.circuitstoday.com/telephone-in-use-indicator

It all worked fine untill I tried to test it by calling into my phone.
(the one test I didnt do before I soldered it all together)

What happens is taht the phone rings for a about 1/2 a ring then stops ringing.
To my surprise when I life the phone up the line is alive eg. Its like the device has answered the phone.

I think that the circuit must be drawing too much power and then telling the phone that it has been answered, because the voltage has gone down.

I have had to replace the Transistors with NTE199, which according to the book are the same. I have also used a rectifier that is a 2 amp 400v SIP 2KBP04M-1.
Im wondering if I used a different rectifier if that would change the results?

I recognize that your not suppse to take power from the phone co. but I would like to get this circuit working. Can anyone tell me why its not working.
thanks.


There's a lot wrong with that circuit, but as an experiment
add a small (10uf or less) electrolytic from the base of
Q2 to ground, then ring your phone to see if it works.

Then, when you've got it working or not, remove it from the
phone line and use the parts for something else. It is not
"phone company friendly" nor are the parts properly V rated.

Old 400E KTU cards (1A2 key phone systems) are floating around
surplus and are made for the phone companies.

Or surely a modem, just uinsg the "DAA" part. Even the "winmodems".

THere has to be an off-hook indicator to tell the modem the line's not
available.

I recall back when this sort of circuit seemed to come up here over a
decade ago, John whatshisname suggested something so that when his modem
went online, it disconnected the other phones in the house. Obviously he
had to arrange things right he could control the rest of the phone wiring
in the house.

Michael

 

[P E Schoen]

"Ian Field" wrote in message news:%VtYs.393090$5F3.188588@fx21.fr7...

The ones I often find in phones are the MPSA42 & 92 - ones PNP & the
other NPN.

You can also scrounge some HV transistors in CFL bulbs. And some fairly good
capacitors and a transformer, and a diac, which can be used to make a
relaxation oscillator to blink an LED without overloading the phone line.

I have wondered how much power can be drawn from the phone line without
causing an error notification to the TELCO. The maximum power is probably
the point at which the line voltage drops to 1/2 the 48 VDC, which may be in
the order of 10 mA, so at 24 VDC it's about 1/4W. You might get away with it
if you go off-hook every 10 seconds or so.

A lot more power could be extracted if you could cause an incoming ring
signal, which is about 100 VAC at 25 Hz and possibly 25-100 mA, maybe 40%
duty cycle, so perhaps a couple of watts.

Paul

 

[Michael A. Terrell]

Michael Black wrote:

Michael A. Terrell wrote:

Old 400E KTU cards (1A2 key phone systems) are floating around
surplus and are made for the phone companies.

Or surely a modem, just uinsg the "DAA" part. Even the "winmodems".
THere has to be an off-hook indicator to tell the modem the line's not
available.

I recall back when this sort of circuit seemed to come up here over a
decade ago, John whatshisname suggested something so that when his modem
went online, it disconnected the other phones in the house. Obviously he
had to arrange things right he could control the rest of the phone wiring
in the house.

That was easy. Connect the real phone line to the second pair.
Connect the modem's line jack to that line, and the phone jack back to
the regular line.

Michael

 

[Jasen Betts]

On 2013-03-03, P E Schoen <paul@peschoen.com> wrote:

"Ian Field" wrote in message news:%VtYs.393090$5F3.188588@fx21.fr7...

The ones I often find in phones are the MPSA42 & 92 - ones PNP & the
other NPN.

You can also scrounge some HV transistors in CFL bulbs. And some fairly good
capacitors and a transformer, and a diac, which can be used to make a
relaxation oscillator to blink an LED without overloading the phone line.

I have wondered how much power can be drawn from the phone line without
causing an error notification to the TELCO. The maximum power is probably
the point at which the line voltage drops to 1/2 the 48 VDC, which may be in
the order of 10 mA, so at 24 VDC it's about 1/4W. You might get away with it
if you go off-hook every 10 seconds or so.

A lot more power could be extracted if you could cause an incoming ring
signal, which is about 100 VAC at 25 Hz and possibly 25-100 mA, maybe 40%
duty cycle, so perhaps a couple of watts.

You draw 10mA and they'll think your phone lines ahva a fault (perhaps
wet)

--
⚂⚃ 100% natural

--- news://freenews.netfront.net/ - complaints: news@netfront.net ---

 

[Jasen Betts]

On 2013-03-03, Michael Black <et472@ncf.ca> wrote:

On Sat, 2 Mar 2013, Michael A. Terrell wrote:


ehsjr wrote:

On 2/28/2013 2:22 PM, steve wrote:
I tested and built the following circuit.

http://www.circuitstoday.com/telephone-in-use-indicator

It all worked fine untill I tried to test it by calling into my phone.
(the one test I didnt do before I soldered it all together)

What happens is taht the phone rings for a about 1/2 a ring then stops ringing.
To my surprise when I life the phone up the line is alive eg. Its like the device has answered the phone.

I think that the circuit must be drawing too much power and then telling the phone that it has been answered, because the voltage has gone down.

I have had to replace the Transistors with NTE199, which according to the book are the same. I have also used a rectifier that is a 2 amp 400v SIP 2KBP04M-1.
Im wondering if I used a different rectifier if that would change the results?

I recognize that your not suppse to take power from the phone co. but I would like to get this circuit working. Can anyone tell me why its not working.
thanks.


There's a lot wrong with that circuit, but as an experiment
add a small (10uf or less) electrolytic from the base of
Q2 to ground, then ring your phone to see if it works.

Then, when you've got it working or not, remove it from the
phone line and use the parts for something else. It is not
"phone company friendly" nor are the parts properly V rated.

Old 400E KTU cards (1A2 key phone systems) are floating around
surplus and are made for the phone companies.

Or surely a modem, just uinsg the "DAA" part. Even the "winmodems".
THere has to be an off-hook indicator to tell the modem the line's not
available.

I recall back when this sort of circuit seemed to come up here over a
decade ago, John whatshisname suggested something so that when his modem
went online, it disconnected the other phones in the house. Obviously he
had to arrange things right he could control the rest of the phone wiring
in the house.

some modems had a switched socket that would be disconnected from
the line when the modem went off-hook, some had the pads but just
had wire links in place of the relay.

A second relay was needed as the main relay was also used for pulse
dialing.



--
⚂⚃ 100% natural

 

[tuinkabouter]

On 2/28/2013 8:22 PM, steve wrote:

I tested and built the following circuit.

http://www.circuitstoday.com/telephone-in-use-indicator

It all worked fine untill I tried to test it by calling into my phone.
(the one test I didnt do before I soldered it all together)

What happens is taht the phone rings for a about 1/2 a ring then stops ringing.
To my surprise when I life the phone up the line is alive eg. Its like the device has answered the phone.

I think that the circuit must be drawing too much power and then telling the phone that it has been answered, because the voltage has gone down.

I have had to replace the Transistors with NTE199, which according to the book are the same. I have also used a rectifier that is a 2 amp 400v SIP 2KBP04M-1.
Im wondering if I used a different rectifier if that would change the results?

I recognize that your not suppse to take power from the phone co. but I would like to get this circuit working. Can anyone tell me why its not working.
thanks.

For off hook indication you can put a led in series with the telephone
line. Across tte led a diode.

Instead of the diode you can use an optocouple and then control whatever
you like.

Old fashion method, a 12 V relais in series.

 

[Jamie]

Michael Black wrote:

On Sat, 2 Mar 2013, Michael A. Terrell wrote:


ehsjr wrote:


On 2/28/2013 2:22 PM, steve wrote:

I tested and built the following circuit.

http://www.circuitstoday.com/telephone-in-use-indicator

It all worked fine untill I tried to test it by calling into my phone.
(the one test I didnt do before I soldered it all together)

What happens is taht the phone rings for a about 1/2 a ring then
stops ringing.
To my surprise when I life the phone up the line is alive eg. Its
like the device has answered the phone.

I think that the circuit must be drawing too much power and then
telling the phone that it has been answered, because the voltage has
gone down.

I have had to replace the Transistors with NTE199, which according
to the book are the same. I have also used a rectifier that is a 2
amp 400v SIP 2KBP04M-1.
Im wondering if I used a different rectifier if that would change
the results?

I recognize that your not suppse to take power from the phone co.
but I would like to get this circuit working. Can anyone tell me why
its not working.
thanks.


There's a lot wrong with that circuit, but as an experiment
add a small (10uf or less) electrolytic from the base of
Q2 to ground, then ring your phone to see if it works.

Then, when you've got it working or not, remove it from the
phone line and use the parts for something else. It is not
"phone company friendly" nor are the parts properly V rated.


Old 400E KTU cards (1A2 key phone systems) are floating around
surplus and are made for the phone companies.

Or surely a modem, just uinsg the "DAA" part. Even the "winmodems".
THere has to be an off-hook indicator to tell the modem the line's not
available.

I recall back when this sort of circuit seemed to come up here over a
decade ago, John whatshisname suggested something so that when his modem
went online, it disconnected the other phones in the house. Obviously
he had to arrange things right he could control the rest of the phone
wiring in the house.

Michael

which is why they made modems with a line in and phone out...

Jamie

 

[Jamie]

Jasen Betts wrote:

On 2013-03-03, Michael Black <et472@ncf.ca> wrote:

On Sat, 2 Mar 2013, Michael A. Terrell wrote:


ehsjr wrote:

On 2/28/2013 2:22 PM, steve wrote:

I tested and built the following circuit.

http://www.circuitstoday.com/telephone-in-use-indicator

It all worked fine untill I tried to test it by calling into my phone.
(the one test I didnt do before I soldered it all together)

What happens is taht the phone rings for a about 1/2 a ring then stops ringing.
To my surprise when I life the phone up the line is alive eg. Its like the device has answered the phone.

I think that the circuit must be drawing too much power and then telling the phone that it has been answered, because the voltage has gone down.

I have had to replace the Transistors with NTE199, which according to the book are the same. I have also used a rectifier that is a 2 amp 400v SIP 2KBP04M-1.
Im wondering if I used a different rectifier if that would change the results?

I recognize that your not suppse to take power from the phone co. but I would like to get this circuit working. Can anyone tell me why its not working.
thanks.


There's a lot wrong with that circuit, but as an experiment
add a small (10uf or less) electrolytic from the base of
Q2 to ground, then ring your phone to see if it works.

Then, when you've got it working or not, remove it from the
phone line and use the parts for something else. It is not
"phone company friendly" nor are the parts properly V rated.

Old 400E KTU cards (1A2 key phone systems) are floating around
surplus and are made for the phone companies.


Or surely a modem, just uinsg the "DAA" part. Even the "winmodems".
THere has to be an off-hook indicator to tell the modem the line's not
available.

I recall back when this sort of circuit seemed to come up here over a
decade ago, John whatshisname suggested something so that when his modem
went online, it disconnected the other phones in the house. Obviously he
had to arrange things right he could control the rest of the phone wiring
in the house.


some modems had a switched socket that would be disconnected from
the line when the modem went off-hook, some had the pads but just
had wire links in place of the relay.

A second relay was needed as the main relay was also used for pulse
dialing.



Seems like in my distance past I used a low voltage low current Reed

relay in series with the phone line with a by pass zener pair to
protect it from higher voltages.

Jamie

 

[Ian Field]

"P E Schoen" <paul@peschoen.com> wrote in message
news:kguke2$94j$1@dont-email.me...

"Ian Field" wrote in message news:%VtYs.393090$5F3.188588@fx21.fr7...

The ones I often find in phones are the MPSA42 & 92 - ones PNP & the
other NPN.

You can also scrounge some HV transistors in CFL bulbs.

Usually of a type similar to MJE13007 - pretty low gain - the base current
alone would probably be more than you can get away with "on hook".

And some fairly good

capacitors and a transformer,

The 220V UK ones have a HF ballast driven by a half-bridge - maybe the 110V
US ones have a transformer.

and a diac, which can be used to make a

relaxation oscillator to blink an LED without overloading the phone line.

I suggested that yesterday - do try to keep up at the back!

 

[Ian Field]

"Jon Kirwan" <jonk@infinitefactors.org> wrote in message
news:3g65j8p5fcrfcn03jtqf57rr1ain4e04tn@4ax.com...

On Sat, 2 Mar 2013 21:22:37 -0000, "Ian Field"
gangprobing.alien@ntlworld.com> wrote:



"Jon Kirwan" <jonk@infinitefactors.org> wrote in message
news:7sm4j81hs4ep7gti49mukuolcvv68unerc@4ax.com...
On Thu, 28 Feb 2013 11:22:00 -0800 (PST), steve
stevesemple@lycos.com> wrote:

I tested and built the following circuit.

http://www.circuitstoday.com/telephone-in-use-indicator

It all worked fine untill I tried to test it by calling into
my phone. (the one test I didnt do before I soldered it all
together)

What happens is taht the phone rings for a about 1/2 a ring
then stops ringing. To my surprise when I life the phone up
the line is alive eg. Its like the device has answered the
phone.

I think that the circuit must be drawing too much power and
then telling the phone that it has been answered, because
the voltage has gone down.

I have had to replace the Transistors with NTE199, which
according to the book are the same. I have also used a
rectifier that is a 2 amp 400v SIP 2KBP04M-1.

Im wondering if I used a different rectifier if that would
change the results?

I recognize that your not suppse to take power from the
phone co. but I would like to get this circuit working. Can
anyone tell me why its not working.

thanks.

There is quite a long specification for telephone lines in
the US. I have a copy, thanks to Don Bowey, when he dropped a
copy over at my home back around 2003 or so. It represents an
industry composite of various systems and includes envelopes
of operation. The gist of it is, as Don wrote before coming
over back then,

"The FCC R&R require a minimum of 5M of customer premises
equipment loop resistance in the on-hook state. Also.
at 220uA some Central Offices will declare a line fault
and remove the line from service."

The basic idea of presenting 5MOhm total customer premises
load (that is the TOTAL of all phones and connected
equipment) when on-hook is incredibly hard to meet with an
unpowered attachment that shows "in use" and "not in use" led
lights.

I've also read that, "if you are in USA or canada Bellcore
specs allow a max of 5micro amps at 48VDC in an on-hook
state." That's 10MOhm, in effect, though I believe the 5MOhm
for the entire premises still fits the spec.

The upshot here is that you aren't going to be seeing an LED
lit continuously and still meet on-hook specifications. You
can design a system to blink periodically,

If you can use that 48V to charge a capacitor above 32V without violating
the on hook current spec; you can make an LED flash very brightly
periodically by dumping the cap into it with a DB3 diac.

You'd have to trial & error for how many uF to make the flash bright
enough
without blowing the LED.

Yeah, that is true enough I suppose. So examine:

http://www.infinitefactors.org/misc/spice/Pulser%202.png

Seems rather elaborate when 1 resistor, 1 capacitor, 1 diac & 1 LED would do
the same job just as well.

 

[Ian Field]

"Jamie" <jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote in message
news:KNIYs.36533$dz5.7008@newsfe07.iad...

Jasen Betts wrote:

On 2013-03-03, Michael Black <et472@ncf.ca> wrote:

On Sat, 2 Mar 2013, Michael A. Terrell wrote:


ehsjr wrote:

On 2/28/2013 2:22 PM, steve wrote:

I tested and built the following circuit.

http://www.circuitstoday.com/telephone-in-use-indicator

It all worked fine untill I tried to test it by calling into my phone.
(the one test I didnt do before I soldered it all together)

What happens is taht the phone rings for a about 1/2 a ring then stops
ringing.
To my surprise when I life the phone up the line is alive eg. Its like
the device has answered the phone.

I think that the circuit must be drawing too much power and then
telling the phone that it has been answered, because the voltage has
gone down.

I have had to replace the Transistors with NTE199, which according to
the book are the same. I have also used a rectifier that is a 2 amp
400v SIP 2KBP04M-1.
Im wondering if I used a different rectifier if that would change the
results?

I recognize that your not suppse to take power from the phone co. but
I would like to get this circuit working. Can anyone tell me why its
not working.
thanks.


There's a lot wrong with that circuit, but as an experiment
add a small (10uf or less) electrolytic from the base of
Q2 to ground, then ring your phone to see if it works.

Then, when you've got it working or not, remove it from the
phone line and use the parts for something else. It is not
"phone company friendly" nor are the parts properly V rated.

Old 400E KTU cards (1A2 key phone systems) are floating around
surplus and are made for the phone companies.


Or surely a modem, just uinsg the "DAA" part. Even the "winmodems".
THere has to be an off-hook indicator to tell the modem the line's not
available.

I recall back when this sort of circuit seemed to come up here over a
decade ago, John whatshisname suggested something so that when his modem
went online, it disconnected the other phones in the house. Obviously he
had to arrange things right he could control the rest of the phone wiring
in the house.


some modems had a switched socket that would be disconnected from
the line when the modem went off-hook, some had the pads but just
had wire links in place of the relay.

A second relay was needed as the main relay was also used for pulse
dialing.



Seems like in my distance past I used a low voltage low current Reed relay
in series with the phone line with a by pass zener pair to
protect it from higher voltages.

Jamie

There was an interesting reed relay project published some years ago to
thwart premium rate rogue diallers.

A coil wound around a standard reed, pulls it in while off hook current
flows to complete the connection - you have to hold down a pushbutton while
the modem initiates the call.

Once the connection is established, the rogue dialler has to drop the line
to dial the premium rate number - without anyone holding down the
pushbutton, this operation fails.

 

[Ian Field]

"tuinkabouter" <dachthetniet@net.invalid> wrote in message
news:kgvktk$8ok$1@dont-email.me...

On 2/28/2013 8:22 PM, steve wrote:
I tested and built the following circuit.

http://www.circuitstoday.com/telephone-in-use-indicator

It all worked fine untill I tried to test it by calling into my phone.
(the one test I didnt do before I soldered it all together)

What happens is taht the phone rings for a about 1/2 a ring then stops
ringing.
To my surprise when I life the phone up the line is alive eg. Its like
the device has answered the phone.

I think that the circuit must be drawing too much power and then telling
the phone that it has been answered, because the voltage has gone down.

I have had to replace the Transistors with NTE199, which according to the
book are the same. I have also used a rectifier that is a 2 amp 400v SIP
2KBP04M-1.
Im wondering if I used a different rectifier if that would change the
results?

I recognize that your not suppse to take power from the phone co. but I
would like to get this circuit working. Can anyone tell me why its not
working.
thanks.

For off hook indication you can put a led in series with the telephone
line. Across tte led a diode.

If it turns out that any current pulses at any time can blow the LED - put 3
silicon diodes in series to make a Vf clamp, you do of course still need the
inverse parallel diode to clamp Vr.

 

[Jon Kirwan]

On Sun, 3 Mar 2013 16:30:33 -0000, "Ian Field"
<gangprobing.alien@ntlworld.com> wrote:

"Jon Kirwan" <jonk@infinitefactors.org> wrote in message
news:3g65j8p5fcrfcn03jtqf57rr1ain4e04tn@4ax.com...
On Sat, 2 Mar 2013 21:22:37 -0000, "Ian Field"
gangprobing.alien@ntlworld.com> wrote:



"Jon Kirwan" <jonk@infinitefactors.org> wrote in message
news:7sm4j81hs4ep7gti49mukuolcvv68unerc@4ax.com...
On Thu, 28 Feb 2013 11:22:00 -0800 (PST), steve
stevesemple@lycos.com> wrote:

I tested and built the following circuit.

http://www.circuitstoday.com/telephone-in-use-indicator

It all worked fine untill I tried to test it by calling into
my phone. (the one test I didnt do before I soldered it all
together)

What happens is taht the phone rings for a about 1/2 a ring
then stops ringing. To my surprise when I life the phone up
the line is alive eg. Its like the device has answered the
phone.

I think that the circuit must be drawing too much power and
then telling the phone that it has been answered, because
the voltage has gone down.

I have had to replace the Transistors with NTE199, which
according to the book are the same. I have also used a
rectifier that is a 2 amp 400v SIP 2KBP04M-1.

Im wondering if I used a different rectifier if that would
change the results?

I recognize that your not suppse to take power from the
phone co. but I would like to get this circuit working. Can
anyone tell me why its not working.

thanks.

There is quite a long specification for telephone lines in
the US. I have a copy, thanks to Don Bowey, when he dropped a
copy over at my home back around 2003 or so. It represents an
industry composite of various systems and includes envelopes
of operation. The gist of it is, as Don wrote before coming
over back then,

"The FCC R&R require a minimum of 5M of customer premises
equipment loop resistance in the on-hook state. Also.
at 220uA some Central Offices will declare a line fault
and remove the line from service."

The basic idea of presenting 5MOhm total customer premises
load (that is the TOTAL of all phones and connected
equipment) when on-hook is incredibly hard to meet with an
unpowered attachment that shows "in use" and "not in use" led
lights.

I've also read that, "if you are in USA or canada Bellcore
specs allow a max of 5micro amps at 48VDC in an on-hook
state." That's 10MOhm, in effect, though I believe the 5MOhm
for the entire premises still fits the spec.

The upshot here is that you aren't going to be seeing an LED
lit continuously and still meet on-hook specifications. You
can design a system to blink periodically,

If you can use that 48V to charge a capacitor above 32V without violating
the on hook current spec; you can make an LED flash very brightly
periodically by dumping the cap into it with a DB3 diac.

You'd have to trial & error for how many uF to make the flash bright
enough
without blowing the LED.

Yeah, that is true enough I suppose. So examine:

http://www.infinitefactors.org/misc/spice/Pulser%202.png

Seems rather elaborate when 1 resistor, 1 capacitor, 1 diac & 1 LED would do
the same job just as well.

It's a reliable design, as I've built a couple, at least.

I've not used diacs, yet. Just a hobbyist. But yes, I can see
how that should work. Breakover voltage is higher, which has
its advantages in this application.

Any particular diac you'd consider trying?

Jon

 

[John Larkin]

On Thu, 28 Feb 2013 18:42:53 -0500, Jamie
<jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote:

steve wrote:
I tested and built the following circuit.

http://www.circuitstoday.com/telephone-in-use-indicator

It all worked fine untill I tried to test it by calling into my phone.
(the one test I didnt do before I soldered it all together)

What happens is taht the phone rings for a about 1/2 a ring then stops ringing.
To my surprise when I life the phone up the line is alive eg. Its like the device has answered the phone.

I think that the circuit must be drawing too much power and then telling the phone that it has been answered, because the voltage has gone down.

I have had to replace the Transistors with NTE199, which according to the book are the same. I have also used a rectifier that is a 2 amp 400v SIP 2KBP04M-1.
Im wondering if I used a different rectifier if that would change the results?

I recognize that your not suppse to take power from the phone co. but I would like to get this circuit working. Can anyone tell me why its not working.
thanks.


I think some one gave you some bad transistor numbers..

THe phone system in the US rings at around 100 Volts AC and on hook
is around 50Volts. Off hook may give you around 10 volts and it depends
on how many phones you have at one time off hook.

The 2N3392 can only handle 25Volts and it may work if you can insure
that the unit will switch on in time to load it down. Further more, the
other transistor will be sitting there with this 50v (on hook), leaking
through the collector.

The NTE199 replacement isn't much better, it has a 70V limit at best
and most likely will work find when on hook, but when it rings, you can
expect some leaking to be taking place.

You first need to get HV transistors.

Try getting some 2N5550 transistors, or the 2N5551 which is a little
higher..
Mouser.com has 2N5551 for 0.78 ech and they have over 3k in stock.


Jamie

How about a pair of back-to-back paralleled LEDs in series with the line? Rings
would be bright, off-hook less bright. Might look cool, especially with
different color LEDs.


--

John Larkin Highland Technology Inc
www.highlandtechnology.com jlarkin at highlandtechnology dot com

Precision electronic instrumentation
Picosecond-resolution Digital Delay and Pulse generators
Custom timing and laser controllers
Photonics and fiberoptic TTL data links
VME analog, thermocouple, LVDT, synchro, tachometer
Multichannel arbitrary waveform generators

 

[Ian Field]

"Jon Kirwan" <jonk@infinitefactors.org> wrote in message
news:7l37j89pon3c6c35lbhgds841uta9eb4fs@4ax.com...

On Sun, 3 Mar 2013 16:30:33 -0000, "Ian Field"
gangprobing.alien@ntlworld.com> wrote:



"Jon Kirwan" <jonk@infinitefactors.org> wrote in message
news:3g65j8p5fcrfcn03jtqf57rr1ain4e04tn@4ax.com...
On Sat, 2 Mar 2013 21:22:37 -0000, "Ian Field"
gangprobing.alien@ntlworld.com> wrote:



"Jon Kirwan" <jonk@infinitefactors.org> wrote in message
news:7sm4j81hs4ep7gti49mukuolcvv68unerc@4ax.com...
On Thu, 28 Feb 2013 11:22:00 -0800 (PST), steve
stevesemple@lycos.com> wrote:

I tested and built the following circuit.

http://www.circuitstoday.com/telephone-in-use-indicator

It all worked fine untill I tried to test it by calling into
my phone. (the one test I didnt do before I soldered it all
together)

What happens is taht the phone rings for a about 1/2 a ring
then stops ringing. To my surprise when I life the phone up
the line is alive eg. Its like the device has answered the
phone.

I think that the circuit must be drawing too much power and
then telling the phone that it has been answered, because
the voltage has gone down.

I have had to replace the Transistors with NTE199, which
according to the book are the same. I have also used a
rectifier that is a 2 amp 400v SIP 2KBP04M-1.

Im wondering if I used a different rectifier if that would
change the results?

I recognize that your not suppse to take power from the
phone co. but I would like to get this circuit working. Can
anyone tell me why its not working.

thanks.

There is quite a long specification for telephone lines in
the US. I have a copy, thanks to Don Bowey, when he dropped a
copy over at my home back around 2003 or so. It represents an
industry composite of various systems and includes envelopes
of operation. The gist of it is, as Don wrote before coming
over back then,

"The FCC R&R require a minimum of 5M of customer premises
equipment loop resistance in the on-hook state. Also.
at 220uA some Central Offices will declare a line fault
and remove the line from service."

The basic idea of presenting 5MOhm total customer premises
load (that is the TOTAL of all phones and connected
equipment) when on-hook is incredibly hard to meet with an
unpowered attachment that shows "in use" and "not in use" led
lights.

I've also read that, "if you are in USA or canada Bellcore
specs allow a max of 5micro amps at 48VDC in an on-hook
state." That's 10MOhm, in effect, though I believe the 5MOhm
for the entire premises still fits the spec.

The upshot here is that you aren't going to be seeing an LED
lit continuously and still meet on-hook specifications. You
can design a system to blink periodically,

If you can use that 48V to charge a capacitor above 32V without
violating
the on hook current spec; you can make an LED flash very brightly
periodically by dumping the cap into it with a DB3 diac.

You'd have to trial & error for how many uF to make the flash bright
enough
without blowing the LED.

Yeah, that is true enough I suppose. So examine:

http://www.infinitefactors.org/misc/spice/Pulser%202.png

Seems rather elaborate when 1 resistor, 1 capacitor, 1 diac & 1 LED would
do
the same job just as well.

It's a reliable design, as I've built a couple, at least.

I've not used diacs, yet. Just a hobbyist. But yes, I can see
how that should work. Breakover voltage is higher, which has
its advantages in this application.

Any particular diac you'd consider trying?

I already suggested the DB3 in the post I sent yesterday.

They're fairly common in UK CFLs, although Philips don't use them in types
less than 18W.

 

[Jamie]

John Larkin wrote:

On Thu, 28 Feb 2013 18:42:53 -0500, Jamie
jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote:


steve wrote:

I tested and built the following circuit.

http://www.circuitstoday.com/telephone-in-use-indicator

It all worked fine untill I tried to test it by calling into my phone.
(the one test I didnt do before I soldered it all together)

What happens is taht the phone rings for a about 1/2 a ring then stops ringing.
To my surprise when I life the phone up the line is alive eg. Its like the device has answered the phone.

I think that the circuit must be drawing too much power and then telling the phone that it has been answered, because the voltage has gone down.

I have had to replace the Transistors with NTE199, which according to the book are the same. I have also used a rectifier that is a 2 amp 400v SIP 2KBP04M-1.
Im wondering if I used a different rectifier if that would change the results?

I recognize that your not suppse to take power from the phone co. but I would like to get this circuit working. Can anyone tell me why its not working.
thanks.


I think some one gave you some bad transistor numbers..

THe phone system in the US rings at around 100 Volts AC and on hook
is around 50Volts. Off hook may give you around 10 volts and it depends
on how many phones you have at one time off hook.

The 2N3392 can only handle 25Volts and it may work if you can insure
that the unit will switch on in time to load it down. Further more, the
other transistor will be sitting there with this 50v (on hook), leaking
through the collector.

The NTE199 replacement isn't much better, it has a 70V limit at best
and most likely will work find when on hook, but when it rings, you can
expect some leaking to be taking place.

You first need to get HV transistors.

Try getting some 2N5550 transistors, or the 2N5551 which is a little
higher..
Mouser.com has 2N5551 for 0.78 ech and they have over 3k in stock.


Jamie


How about a pair of back-to-back paralleled LEDs in series with the line? Rings
would be bright, off-hook less bright. Might look cool, especially with
different color LEDs.

Not sure how the audio would sound going through diodes.

Jamie

 

[Ian Field]

"Jamie" <jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote in message
news:ISMYs.81579$KR.62297@newsfe27.iad...

John Larkin wrote:

On Thu, 28 Feb 2013 18:42:53 -0500, Jamie
jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote:


steve wrote:

I tested and built the following circuit.

http://www.circuitstoday.com/telephone-in-use-indicator

It all worked fine untill I tried to test it by calling into my phone.
(the one test I didnt do before I soldered it all together)

What happens is taht the phone rings for a about 1/2 a ring then stops
ringing.
To my surprise when I life the phone up the line is alive eg. Its like
the device has answered the phone.

I think that the circuit must be drawing too much power and then telling
the phone that it has been answered, because the voltage has gone down.
I have had to replace the Transistors with NTE199, which according to
the book are the same. I have also used a rectifier that is a 2 amp 400v
SIP 2KBP04M-1.
Im wondering if I used a different rectifier if that would change the
results?

I recognize that your not suppse to take power from the phone co. but I
would like to get this circuit working. Can anyone tell me why its not
working.
thanks.


I think some one gave you some bad transistor numbers..

THe phone system in the US rings at around 100 Volts AC and on hook is
around 50Volts. Off hook may give you around 10 volts and it depends on
how many phones you have at one time off hook.

The 2N3392 can only handle 25Volts and it may work if you can insure
that the unit will switch on in time to load it down. Further more, the
other transistor will be sitting there with this 50v (on hook), leaking
through the collector.

The NTE199 replacement isn't much better, it has a 70V limit at best and
most likely will work find when on hook, but when it rings, you can
expect some leaking to be taking place.

You first need to get HV transistors.

Try getting some 2N5550 transistors, or the 2N5551 which is a little
higher..
Mouser.com has 2N5551 for 0.78 ech and they have over 3k in stock.


Jamie


How about a pair of back-to-back paralleled LEDs in series with the line?
Rings
would be bright, off-hook less bright. Might look cool, especially with
different color LEDs.



Not sure how the audio would sound going through diodes.

Like about 1 3/4V of crossover distortion on a 48V signal.