Phone in use circuit not working

[steve]

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.

 

[Peabody]

steve says...

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.

That sounds right. The phone company senses an off-hook
state based on DC current passing through the local loop.
So your explanation makes sense.

I think your part substitutions are correct. But I wonder
if you have the bridge rectifier wired correctly - the phone
lines connected to the ~ pins. Or, could that part be
faulty?

If everything is wired correctly, try removing R4 from the
circuit and see if ringing works properly then. If it does,
then you may just need a higher value resistor for R1.

Actually, I don't much care for the circuit. During each
cycle of the ring signal, the voltage on your circuit will
go to zero. It won't go negative because of the rectifier,
but it will go to zero. As it gets near zero, then again as
it comes back up, Q2 will turn on for a bit, and current
will flow, until the voltage gets high enough to turn on Q1,
which will turn off Q2. But during that Q2-on period, maybe
enough current will flow to signal an off-hook to the
central office. Well, I'm clearly just guessing, but I find
myself wanting to put a capacitor from the base of Q1 to
ground.

Anyway, good luck.

 

[steve]

Thank you for your comments.

Well I have wired the phone line to the middle pins on the SIP [ + | | - ]
And + to plus and - to Neg of the diagram.

Thanks for the tips. I will try them.

By the way one thing. The diagram calls for R2 to be 33k. But a comment on the bottom says that the value should be the same as R1 3.3. So I made R2 3..3. I asumed that the poster was right, because I know how scematics get screwed up some times. In your opinion should R2 be 3.3k or 33k. Maybe thats whats wrong?
Regards.

 

[Peabody]

steve says...

Well I have wired the phone line to the middle pins on
the SIP [ + | | - ] And + to plus and - to Neg of the
diagram.

Yes, I think that's right.

By the way one thing. The diagram calls for R2 to be
33k. But a comment on the bottom says that the value
should be the same as R1 3.3. So I made R2 3.3. I asumed
that the poster was right, because I know how scematics
get screwed up some times. In your opinion should R2 be
3.3k or 33k. Maybe thats whats wrong?

Well, using 33k will make the circuit draw less current, but
the green LED probably will not light up enough to be
visible. But of course you really don't need the green LED,
just the red one.

My concern is that the circuit just draws too much current,
and therefore shows as off-hook. I would try it at 33k, and
take the green LED out (or just temporarily jumper across
it, and see if it works. Beyond that, you could increase
the resistance of R1, but then that will make the red LED
dimmer.

There is another version of this circuit that uses MOSFETs
instead of NPN transistors, and all but the LED resistor are
in megohms, so it draws very little current when on-hook.
That's because the MOSFETs switch based on voltage instead
of current.

http://www.zen22142.zen.co.uk/Circuits/Misc/tiuc.htm

 

[Jamie]

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

 

[Jamie]

Peabody wrote:

steve says...

Well I have wired the phone line to the middle pins on
the SIP [ + | | - ] And + to plus and - to Neg of the
diagram.

Yes, I think that's right.

By the way one thing. The diagram calls for R2 to be
33k. But a comment on the bottom says that the value
should be the same as R1 3.3. So I made R2 3.3. I asumed
that the poster was right, because I know how scematics
get screwed up some times. In your opinion should R2 be
3.3k or 33k. Maybe thats whats wrong?

Well, using 33k will make the circuit draw less current, but
the green LED probably will not light up enough to be
visible. But of course you really don't need the green LED,
just the red one.

My concern is that the circuit just draws too much current,
and therefore shows as off-hook. I would try it at 33k, and
take the green LED out (or just temporarily jumper across
it, and see if it works. Beyond that, you could increase
the resistance of R1, but then that will make the red LED
dimmer.

There is another version of this circuit that uses MOSFETs
instead of NPN transistors, and all but the LED resistor are
in megohms, so it draws very little current when on-hook.
That's because the MOSFETs switch based on voltage instead
of current.

http://www.zen22142.zen.co.uk/Circuits/Misc/tiuc.htm


That one would most likely work better, at least the transistors

are rated at 200V, which is your biggest problem with the first
circuit..

Also this circuit has much less load since it seems to only work
when off hook.

Jamie

 

[amdx]

On 2/28/2013 6:30 PM, Jamie wrote:

Peabody wrote:

steve says...

Well I have wired the phone line to the middle pins on
the SIP [ + | | - ] And + to plus and - to Neg of the
diagram.

Yes, I think that's right.

By the way one thing. The diagram calls for R2 to be
33k. But a comment on the bottom says that the value
should be the same as R1 3.3. So I made R2 3.3. I asumed
that the poster was right, because I know how scematics
get screwed up some times. In your opinion should R2 be
3.3k or 33k. Maybe thats whats wrong?

Well, using 33k will make the circuit draw less current, but
the green LED probably will not light up enough to be
visible. But of course you really don't need the green LED,
just the red one.

My concern is that the circuit just draws too much current,
and therefore shows as off-hook. I would try it at 33k, and
take the green LED out (or just temporarily jumper across
it, and see if it works. Beyond that, you could increase
the resistance of R1, but then that will make the red LED
dimmer.

There is another version of this circuit that uses MOSFETs
instead of NPN transistors, and all but the LED resistor are
in megohms, so it draws very little current when on-hook.
That's because the MOSFETs switch based on voltage instead
of current.

http://www.zen22142.zen.co.uk/Circuits/Misc/tiuc.htm


That one would most likely work better, at least the transistors
are rated at 200V, which is your biggest problem with the first
circuit..

Also this circuit has much less load since it seems to only work
when off hook.

Jamie

Here's one I used for years without problem.

Similar to what Peabody posted, one less FET.
http://i395.photobucket.com/albums/pp37/Qmavam/PhoneLineInUseIndicator_zpsf78c4525.png
I can't find the original URL.
Mikek

 

[Jamie]

amdx wrote:

On 2/28/2013 6:30 PM, Jamie wrote:

Peabody wrote:

steve says...

Well I have wired the phone line to the middle pins on
the SIP [ + | | - ] And + to plus and - to Neg of the
diagram.

Yes, I think that's right.

By the way one thing. The diagram calls for R2 to be
33k. But a comment on the bottom says that the value
should be the same as R1 3.3. So I made R2 3.3. I asumed
that the poster was right, because I know how scematics
get screwed up some times. In your opinion should R2 be
3.3k or 33k. Maybe thats whats wrong?

Well, using 33k will make the circuit draw less current, but
the green LED probably will not light up enough to be
visible. But of course you really don't need the green LED,
just the red one.

My concern is that the circuit just draws too much current,
and therefore shows as off-hook. I would try it at 33k, and
take the green LED out (or just temporarily jumper across
it, and see if it works. Beyond that, you could increase
the resistance of R1, but then that will make the red LED
dimmer.

There is another version of this circuit that uses MOSFETs
instead of NPN transistors, and all but the LED resistor are
in megohms, so it draws very little current when on-hook.
That's because the MOSFETs switch based on voltage instead
of current.

http://www.zen22142.zen.co.uk/Circuits/Misc/tiuc.htm


That one would most likely work better, at least the transistors
are rated at 200V, which is your biggest problem with the first
circuit..

Also this circuit has much less load since it seems to only work
when off hook.

Jamie

Here's one I used for years without problem.
Similar to what Peabody posted, one less FET.
http://i395.photobucket.com/albums/pp37/Qmavam/PhoneLineInUseIndicator_zpsf78c4525.png

I can't find the original URL.
Mikek

I remember buying an off hook relay module for a phone line from radio

shaft years ago, back in the old days, it never worked.

would never switch on. Also, they stopped selling them. Must of been a
reason for it

Some times it is more sensible to buy ready made over making it.


Jamie

 

[Peabody]

amdx says...

Similar to what Peabody posted, one less FET.

http://i395.photobucket.com/albums/pp37/Qmavam/PhoneLineInUseIndic
ator_zpsf78c4525.png

Yes, and that has the capacitor I kept wanting to put into
the first circuit. That should delay the turn-on of the FET
enough to keep the LED off during ringing.

 

[Daniel Pitts]

On 2/28/13 11:22 AM, 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 remember as a teenager, I was playing around with the phone line. I
learned two things. One, if you hook the right resistance across the
line, incoming calls get a "busy" signal, but you can still make
outgoing calls. Two, when someone is calling you, you can get a jolt if
you're holding both ends of the line.

So, when the phone rings, you get a 60V AC signal. Perhaps you need
slightly more resistance in the line. Unless D2 is already too dim, I'd
try changing R1 to a higher resistance.

 

[Michael A. Terrell]

Daniel Pitts wrote:

On 2/28/13 11:22 AM, 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 remember as a teenager, I was playing around with the phone line. I
learned two things. One, if you hook the right resistance across the
line, incoming calls get a "busy" signal, but you can still make
outgoing calls. Two, when someone is calling you, you can get a jolt if
you're holding both ends of the line.

So, when the phone rings, you get a 60V AC signal. Perhaps you need
slightly more resistance in the line. Unless D2 is already too dim, I'd
try changing R1 to a higher resistance.

It was 90 volts.

 

[Michael Black]

On Fri, 1 Mar 2013, Michael A. Terrell wrote:

I remember as a teenager, I was playing around with the phone line. I
learned two things. One, if you hook the right resistance across the
line, incoming calls get a "busy" signal, but you can still make
outgoing calls. Two, when someone is calling you, you can get a jolt if
you're holding both ends of the line.

So, when the phone rings, you get a 60V AC signal. Perhaps you need
slightly more resistance in the line. Unless D2 is already too dim, I'd
try changing R1 to a higher resistance.

It was 90 volts.

Sticking your fingers across a voltage source was never a precise means of

measuring voltage.

Michael

 

[Jasen Betts]

On 2013-02-28, steve <stevesemple@lycos.com> wrote:

Thank you for your comments.

Well I have wired the phone line to the middle pins on the SIP [ + | | - ]
And + to plus and - to Neg of the diagram.

Thanks for the tips. I will try them.

By the way one thing. The diagram calls for R2 to be 33k. But a
comment on the bottom says that the value should be the same as R1
3.3. So I made R2 3.3. I asumed that the poster was right, because I
know how scematics get screwed up some times. In your opinion should
R2 be 3.3k or 33k. Maybe thats whats wrong?
Regards.

33K looks right to me, if perhaps a little too low.

the green LED illuminates when the circuit is off-hook which
is 40V or more. 33K only gets you ballpark 1.3mA, but much more
than that and it'll start looking like off-hook.

If you want it to be brighter get a better LED or connect several
LEDs in series.


--
⚂⚃ 100% natural

 

[Jon Kirwan]

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, by drawing very
little current onto a capacitor, which charges slowly up and
is then discharged into an LED when the voltage rises to the
trigger voltage. You can design that to meet specifications.
But that's not what you've been given to build.

Jon

 

[Michael A. Terrell]

Michael Black wrote:

On Fri, 1 Mar 2013, Michael A. Terrell wrote:

I remember as a teenager, I was playing around with the phone line. I
learned two things. One, if you hook the right resistance across the
line, incoming calls get a "busy" signal, but you can still make
outgoing calls. Two, when someone is calling you, you can get a jolt if
you're holding both ends of the line.

So, when the phone rings, you get a 60V AC signal. Perhaps you need
slightly more resistance in the line. Unless D2 is already too dim, I'd
try changing R1 to a higher resistance.

It was 90 volts.

Sticking your fingers across a voltage source was never a precise means of
measuring voltage.

That's why I bought & built a Heathkit VTVM when I was 13.

 

[Ian Field]

"Peabody" <waybackNO746SPAM44@yahoo.com> wrote in message
news:20130228-231946.484.0@news.astraweb.com...

steve says...

Well I have wired the phone line to the middle pins on
the SIP [ + | | - ] And + to plus and - to Neg of the
diagram.

Yes, I think that's right.

By the way one thing. The diagram calls for R2 to be
33k. But a comment on the bottom says that the value
should be the same as R1 3.3. So I made R2 3.3. I asumed
that the poster was right, because I know how scematics
get screwed up some times. In your opinion should R2 be
3.3k or 33k. Maybe thats whats wrong?

Well, using 33k will make the circuit draw less current, but
the green LED probably will not light up enough to be
visible. But of course you really don't need the green LED,
just the red one.

There are various sources of the specifications that the on/off hook
threshold can be looked up, then it should be a few simple calculations to
determine the circuit's current draw.

Its not uncommon to draw *some* current on hook - many phones maintain a
supercap for various memory functions.

Assuming an LED doesn't violate the on hook current threshold, maybe a
MOSFET (2N7000 etc) could be worked in as its voltage driven rather than
needing base current.

Its worth bearing in mind; there's usually a zener or two downstream of the
bridge rectifier in a phone (typically 12V) - but usually some series
resistance as well, so the voltage off hook will settle a little higher.

 

[Ian Field]

"Jamie" <jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote in message
news:AuSXs.178562$kp4.52700@newsfe09.iad...

Peabody wrote:

steve says...

Well I have wired the phone line to the middle pins on
the SIP [ + | | - ] And + to plus and - to Neg of the
diagram.

Yes, I think that's right.

By the way one thing. The diagram calls for R2 to be
33k. But a comment on the bottom says that the value
should be the same as R1 3.3. So I made R2 3.3. I asumed
that the poster was right, because I know how scematics
get screwed up some times. In your opinion should R2 be
3.3k or 33k. Maybe thats whats wrong?

Well, using 33k will make the circuit draw less current, but
the green LED probably will not light up enough to be
visible. But of course you really don't need the green LED,
just the red one.

My concern is that the circuit just draws too much current,
and therefore shows as off-hook. I would try it at 33k, and
take the green LED out (or just temporarily jumper across
it, and see if it works. Beyond that, you could increase
the resistance of R1, but then that will make the red LED
dimmer.

There is another version of this circuit that uses MOSFETs
instead of NPN transistors, and all but the LED resistor are
in megohms, so it draws very little current when on-hook.
That's because the MOSFETs switch based on voltage instead
of current.

http://www.zen22142.zen.co.uk/Circuits/Misc/tiuc.htm


That one would most likely work better, at least the transistors
are rated at 200V, which is your biggest problem with the first
circuit..

Apparently telcos sometimes apply test voltages upto 200V, but the normal
operating voltage is considerably lower.

220V MOVs & gas discharge arrestors are commonplace in telecoms equipment,
the last phone I stripped & traced had a 200V sidac.

 

[Ian Field]

"Jamie" <jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote in message
news:rpUXs.80033$lC2.51131@newsfe25.iad...

amdx wrote:

On 2/28/2013 6:30 PM, Jamie wrote:

Peabody wrote:

steve says...

Well I have wired the phone line to the middle pins on
the SIP [ + | | - ] And + to plus and - to Neg of the
diagram.

Yes, I think that's right.

By the way one thing. The diagram calls for R2 to be
33k. But a comment on the bottom says that the value
should be the same as R1 3.3. So I made R2 3.3. I asumed
that the poster was right, because I know how scematics
get screwed up some times. In your opinion should R2 be
3.3k or 33k. Maybe thats whats wrong?

Well, using 33k will make the circuit draw less current, but
the green LED probably will not light up enough to be
visible. But of course you really don't need the green LED,
just the red one.

My concern is that the circuit just draws too much current,
and therefore shows as off-hook. I would try it at 33k, and
take the green LED out (or just temporarily jumper across
it, and see if it works. Beyond that, you could increase
the resistance of R1, but then that will make the red LED
dimmer.

There is another version of this circuit that uses MOSFETs
instead of NPN transistors, and all but the LED resistor are
in megohms, so it draws very little current when on-hook.
That's because the MOSFETs switch based on voltage instead
of current.

http://www.zen22142.zen.co.uk/Circuits/Misc/tiuc.htm


That one would most likely work better, at least the transistors
are rated at 200V, which is your biggest problem with the first
circuit..

Also this circuit has much less load since it seems to only work
when off hook.

Jamie

Here's one I used for years without problem.
Similar to what Peabody posted, one less FET.
http://i395.photobucket.com/albums/pp37/Qmavam/PhoneLineInUseIndicator_zpsf78c4525.png I
can't find the original URL.
Mikek

I remember buying an off hook relay module for a phone line from radio
shaft years ago, back in the old days, it never worked.

would never switch on. Also, they stopped selling them. Must of been a
reason for it

Some times it is more sensible to buy ready made over making it.

With all the discount stores sprouting like weeds, there's many things I
once would've built are now cheaper than the parts to buy.

 

[Ian Field]

"Jamie" <jamie_ka1lpa_not_valid_after_ka1lpa_@charter.net> wrote in message
news:cORXs.52295$BV7.11863@newsfe24.iad...

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.

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

 

[Ian Field]

"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.