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
Phone in use circuit not working
Started by ●February 28, 2013
Reply by ●March 2, 20132013-03-02
Reply by ●March 2, 20132013-03-02
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
Reply by ●March 2, 20132013-03-02
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.
Reply by ●March 3, 20132013-03-03
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
Reply by ●March 3, 20132013-03-03
"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=20 capacitors and a transformer, and a diac, which can be used to make a=20 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=20 causing an error notification to the TELCO. The maximum power is = probably=20 the point at which the line voltage drops to 1/2 the 48 VDC, which may = be in=20 the order of 10 mA, so at 24 VDC it's about 1/4W. You might get away = with it=20 if you go off-hook every 10 seconds or so. A lot more power could be extracted if you could cause an incoming ring=20 signal, which is about 100 VAC at 25 Hz and possibly 25-100 mA, maybe = 40%=20 duty cycle, so perhaps a couple of watts. Paul=20
Reply by ●March 3, 20132013-03-03
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
Reply by ●March 3, 20132013-03-03
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 ---
Reply by ●March 3, 20132013-03-03
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
Reply by ●March 3, 20132013-03-03
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.
Reply by ●March 3, 20132013-03-03
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
