If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
|
Thread Tools | Display Modes |
#1
|
|||
|
|||
AT&T Broadband ?
My service went out and AT&T ran a diagnostic and said my router went
out and they would send a new one. While waiting I decided to try my router at a neighbor's house who also has AT&T broadband and it worked OK there so I called them back and they will eventually send a tech out to repair the line. At the wires coming into my house I only got a reading of 2mv ac I know back in the days of landline and DSL the voltage should have been 48vdc as best as I recall...however I don't know what a normal voltage would be for broadband. Anyone here have that knowledge? Thanks Fortunately I can tether my machine to my smartphone to post this. |
#2
|
|||
|
|||
AT&T Broadband ?
On 8/25/2018 3:59 AM, philo wrote:
My service went out and AT&T ran a diagnostic and said my router went out and they would send a new one. While waiting I decided to try my router at a neighbor's house who also has AT&T broadband and it worked OK there so I called them back and they will eventually send a tech out to repair the line. At the wires coming into my house I only got a reading of 2mv ac I know back in the days of landline and DSL the voltage should have been 48vdc as best as I recall...however I don't know what a normal voltage would be for broadband. Anyone here have that knowledge? Thanks Fortunately I can tether my machine to my smartphone to post this. Do you have phone service on that phone line? If not it may be a 'dry loop', in which case I'd expect you'd see a lot less DC, if any. "A dry loop is an unconditioned leased pair of telephone line from a telephone company. The pair does not provide dial tone or battery (continuous electric potential), as opposed to a wet pair, a line usually without dial tone but with battery." https://en.wikipedia.org/wiki/Dry_loop |
#3
|
|||
|
|||
AT&T Broadband ?
philo wrote:
My service went out and AT&T ran a diagnostic and said my router went out and they would send a new one. While waiting I decided to try my router at a neighbor's house who also has AT&T broadband and it worked OK there so I called them back and they will eventually send a tech out to repair the line. At the wires coming into my house I only got a reading of 2mv ac I know back in the days of landline and DSL the voltage should have been 48vdc as best as I recall...however I don't know what a normal voltage would be for broadband. Anyone here have that knowledge? Thanks Fortunately I can tether my machine to my smartphone to post this. http://www.dslreports.com/forum/r412...for-DSL-to-run "Since ADSL can be deployed on a dry pair with no DC bias whatsoever, it's not too surprising that it shows so low." If POTS service has specifically been removed, there's no reason for -48V to be on the line. Neither would you expect the occasional 180VAC at 25Hz for ringing voltage. If you had combo service, the "phone filter" passes DC to 8KHz to the phone. The ADSL needs the 25KHz or higher part. The phone filter is necessary, so the higher frequency signals don't alias down into the voice band. ADSL starts at 25KHz and extends upwards (1.5MHz or higher). It depends on the standard involved, as to how high the highest frequency is. You expect the launch amplitude to be significant, because the line loss could be 50dB or more by the time it gets to the other end. When you have a pedestal at the corner serving ADSL, then not as much signal might be needed (the box may not be designed to drive 18000 feet of wire, but designed for a shorter max distance). https://www.eetimes.com/document.asp?doc_id=1224781 "Assuming a line impedance of 100 ohms, the resulting RMS voltage is 3.31 volts and the RMS current is 33 mA." And notice they're using transformers and differential circuits for it too. Wouldn't be good for DC to be shoved through the transformer (saturation issue). That article was written in the year 2000. I no longer have a "convenient" access point, to take a reading off the line hot. The demarc used to use those nice brass screw terminals, and I could take a reading off that easily. When the installer came in, he defeated my easy access point. Now, I'd need to get into the RJ11 junction box to take a reading. Paul |
#4
|
|||
|
|||
AT&T Broadband ?
On 8/25/2018 7:10 AM, Mike S wrote:
Fortunately I can tether my machine to my smartphone to post this. Do you have phone service on that phone line? If not it may be a 'dry loop', in which case I'd expect you'd see a lot less DC, if any. "A dry loop is an unconditioned leased pair of telephone line from a telephone company. The pair does not provide dial tone or battery (continuous electric potential), as opposed to a wet pair, a line usually without dial tone but with battery." https://en.wikipedia.org/wiki/Dry_loop I do not have a land line so suspect this is not a dry loop, thank you |
#5
|
|||
|
|||
AT&T Broadband ?
On 8/25/2018 8:06 AM, Paul wrote:
philo wrote: My service went out and AT&T ran a diagnostic and said my router went out and they would send a new one. While waiting I decided to try my router at a neighbor's house who also has AT&T broadband and it worked OK there so I called them back and they will eventually send a tech out to repair the line. At the wires coming into my house I only got a reading of 2mv ac I know back in the days of landline and DSL the voltage should have been 48vdc as best as I recall...however I don't know what a normal voltage would be for broadband. Anyone here have that knowledge? Thanks Fortunately I can tether my machine to my smartphone to post this. http://www.dslreports.com/forum/r412...for-DSL-to-run Â*Â* "Since ADSL can be deployed on a dry pair with no DC bias whatsoever, Â*Â*Â* it's not too surprising that it shows so low." If POTS service has specifically been removed, there's no reason for -48V to be on the line. Neither would you expect the occasional 180VAC at 25Hz for ringing voltage. If you had combo service, the "phone filter" passes DC to 8KHz to the phone. The ADSL needs the 25KHz or higher part. The phone filter is necessary, so the higher frequency signals don't alias down into the voice band. ADSL starts at 25KHz and extends upwards (1.5MHz or higher). It depends on the standard involved, as to how high the highest frequency is. You expect the launch amplitude to be significant, because the line loss could be 50dB or more by the time it gets to the other end. When you have a pedestal at the corner serving ADSL, then not as much signal might be needed (the box may not be designed to drive 18000 feet of wire, but designed for a shorter max distance). https://www.eetimes.com/document.asp?doc_id=1224781 Â*Â* "Assuming a line impedance of 100 ohms, the resulting Â*Â*Â* RMS voltage is 3.31 volts and the RMS current is 33 mA." And notice they're using transformers and differential circuits for it too. Wouldn't be good for DC to be shoved through the transformer (saturation issue). That article was written in the year 2000. I no longer have a "convenient" access point, to take a reading off the line hot. The demarc used to use those nice brass screw terminals, and I could take a reading off that easily. When the installer came in, he defeated my easy access point. Now, I'd need to get into the RJ11 junction box to take a reading. Â*Â* Paul I have all the tools I need to get to the AT&T input and there is no voltage there either dc or ac (other than a tiny stray voltage one could expect being picked up on a long wire run) Thank you for confirming my suspicion that there should be at least a few volts there. My frequency meter died years ago and I have no justification for replacing it. BTW: It is very sad that AT&T now has terrible service, they won't get here until Thursday. When I had a problem two years ago from the time I called until the time they came out and had it all fixed was 90 minutes. I spent more time than that just on the phone. |
#6
|
|||
|
|||
AT&T Broadband ?
philo wrote:
On 8/25/2018 8:06 AM, Paul wrote: philo wrote: My service went out and AT&T ran a diagnostic and said my router went out and they would send a new one. While waiting I decided to try my router at a neighbor's house who also has AT&T broadband and it worked OK there so I called them back and they will eventually send a tech out to repair the line. At the wires coming into my house I only got a reading of 2mv ac I know back in the days of landline and DSL the voltage should have been 48vdc as best as I recall...however I don't know what a normal voltage would be for broadband. Anyone here have that knowledge? Thanks Fortunately I can tether my machine to my smartphone to post this. http://www.dslreports.com/forum/r412...for-DSL-to-run "Since ADSL can be deployed on a dry pair with no DC bias whatsoever, it's not too surprising that it shows so low." If POTS service has specifically been removed, there's no reason for -48V to be on the line. Neither would you expect the occasional 180VAC at 25Hz for ringing voltage. If you had combo service, the "phone filter" passes DC to 8KHz to the phone. The ADSL needs the 25KHz or higher part. The phone filter is necessary, so the higher frequency signals don't alias down into the voice band. ADSL starts at 25KHz and extends upwards (1.5MHz or higher). It depends on the standard involved, as to how high the highest frequency is. You expect the launch amplitude to be significant, because the line loss could be 50dB or more by the time it gets to the other end. When you have a pedestal at the corner serving ADSL, then not as much signal might be needed (the box may not be designed to drive 18000 feet of wire, but designed for a shorter max distance). https://www.eetimes.com/document.asp?doc_id=1224781 "Assuming a line impedance of 100 ohms, the resulting RMS voltage is 3.31 volts and the RMS current is 33 mA." And notice they're using transformers and differential circuits for it too. Wouldn't be good for DC to be shoved through the transformer (saturation issue). That article was written in the year 2000. I no longer have a "convenient" access point, to take a reading off the line hot. The demarc used to use those nice brass screw terminals, and I could take a reading off that easily. When the installer came in, he defeated my easy access point. Now, I'd need to get into the RJ11 junction box to take a reading. Paul I have all the tools I need to get to the AT&T input and there is no voltage there either dc or ac (other than a tiny stray voltage one could expect being picked up on a long wire run) Thank you for confirming my suspicion that there should be at least a few volts there. My frequency meter died years ago and I have no justification for replacing it. BTW: It is very sad that AT&T now has terrible service, they won't get here until Thursday. When I had a problem two years ago from the time I called until the time they came out and had it all fixed was 90 minutes. I spent more time than that just on the phone. Here's an example of the ADSL startup sequence. https://s22.postimg.cc/56dmtrxlt/DSL...r_Page_148.gif The customer premise end sends "phase reversals every 16ms". Which, roughly translated, is a 60Hz square wave ? Only then does the AT&T end enable its line driver, and send C-TONES. Initially I tried Google searches on "pilot tone" or similar, thinking there was always a signal on the line. It turns out, that the frequency bins in the upstream and downstream have one bin which operates at constant amplitude and is not modulated. And that's a pilot tone that the DSP can use in the frequency domain. But all that stuff only exists when everything is up and operational. Whereas the initiation sequence is much more crude. And starts with silence. it's quite possible your modem "goes first". Paul |
#7
|
|||
|
|||
AT&T Broadband ?
On 8/25/2018 10:50 AM, Paul wrote:
philo wrote:ice b That article was written in the year 2000. I no longer have a "convenient" access point, to take a reading off the line hot. The demarc used to use those nice brass screw terminals, and I could take a reading off that easily. When the installer came in, he defeated my easy access point. Now, I'd need to get into the RJ11 junction box to take a reading. Â*Â*Â* Paul I have all the tools I need to get to the AT&T input and there is no voltage there either dc or ac (other than a tiny stray voltage one could expect being picked up on a long wire run) Thank you for confirming my suspicion that there should be at least a few volts there. My frequency meter died years ago and I have no justification for replacing it. BTW: It is very sad that AT&T now has terrible service, they won't get here until Thursday. When I had a problem two years ago from the time I called until the time they came out and had it all fixed was 90 minutes. I spent more time than that just on the phone. Here's an example of the ADSL startup sequence. https://s22.postimg.cc/56dmtrxlt/DSL...r_Page_148.gif The customer premise end sends "phase reversals every 16ms". Which, roughly translated, is a 60Hz square wave ? Only then does the AT&T end enable its line driver, and send C-TONES. Initially I tried Google searches on "pilot tone" or similar, thinking there was always a signal on the line. It turns out, that the frequency bins in the upstream and downstream have one bin which operates at constant amplitude and is not modulated. And that's a pilot tone that the DSP can use in the frequency domain. But all that stuff only exists when everything is up and operational. Whereas the initiation sequence is much more crude. And starts with silence. it's quite possible your modem "goes first". Â*Â* Paul What made me distrust the AT&T diagnostic was their presumption that their router was bad if they could not communicate with it. Though it could of course be bad, their line could just as well have been open. The second person I talked to understood the logic and I did not have to waste too much time on the phone before she agreed that a tech needed to be sent out. The first person I talked to had me on the phone for an hour running various tests. Oh well, someone will hopefully be here on Thursday. I will probably not check back in here until my service is restored |
#8
|
|||
|
|||
AT&T Broadband ?
On 8/26/2018 11:41 AM, philo wrote:
On 8/25/2018 10:50 AM, Paul wrote: philo wrote:ice b That article was written in the year 2000. I no longer have a "convenient" access point, to take a reading off the line hot. The demarc used to use those nice brass screw terminals, and I could take a reading off that easily. When the installer came in, he defeated my easy access point. Now, I'd need to get into the RJ11 junction box to take a reading. Â*Â*Â* Paul I have all the tools I need to get to the AT&T input and there is no voltage there either dc or ac (other than a tiny stray voltage one could expect being picked up on a long wire run) Thank you for confirming my suspicion that there should be at least a few volts there. My frequency meter died years ago and I have no justification for replacing it. BTW: It is very sad that AT&T now has terrible service, they won't get here until Thursday. When I had a problem two years ago from the time I called until the time they came out and had it all fixed was 90 minutes. I spent more time than that just on the phone. Here's an example of the ADSL startup sequence. https://s22.postimg.cc/56dmtrxlt/DSL...r_Page_148.gif The customer premise end sends "phase reversals every 16ms". Which, roughly translated, is a 60Hz square wave ? Only then does the AT&T end enable its line driver, and send C-TONES. Initially I tried Google searches on "pilot tone" or similar, thinking there was always a signal on the line. It turns out, that the frequency bins in the upstream and downstream have one bin which operates at constant amplitude and is not modulated. And that's a pilot tone that the DSP can use in the frequency domain. But all that stuff only exists when everything is up and operational. Whereas the initiation sequence is much more crude. And starts with silence. it's quite possible your modem "goes first". Â*Â*Â* Paul What made me distrust the AT&T diagnostic was their presumption that their router was bad if they could not communicate with it. Though it could of course be bad, their line could just as well have been open. The second person I talked to understood the logic and I did not have to waste too much time on the phone before she agreed that a tech needed to be sent out. The first person I talked to had me on the phone for an hour running various tests. Oh well, someone will hopefully be here on Thursday. I will probably not check back in here until my service is restored FWIW, I have AT&T uVerse broadband. Each time I've had an isolated outage (meaning one affecting only my service, not like when head-end equipment failed) the problem has been the cables and each time the 'service' people at AT&T determined that the problem was _absolutely_ with my modem. The first time they insisted that I swap modems. After that phone call I took a walk up the street and located the point where the cable had broken. The next time I took the walk _first_ and located the break. The third time I located the point where it had been cut deliberately because the wire tech from the second call had done a sloppy job of installing new cable and put the splice in a more convenient location at head height on the pole which somebody decided would be entertaining to rip out. |
#9
|
|||
|
|||
AT&T Broadband ?
On 8/26/2018 2:17 PM, John McGaw wrote:
On 8/26/2018 11:41 AM, philo wrote: On 8/25/2018 10:50 AM, Paul wrote: philo wrote:ice b That article was written in the year 2000. I no longer have a "convenient" access point, to take a reading off the line hot. The demarc used to use those nice brass screw terminals, and I could take a reading off that easily. When the installer came in, he defeated my easy access point. Now, I'd need to get into the RJ11 junction box to take a reading. Â*Â*Â* Paul I have all the tools I need to get to the AT&T input and there is no voltage there either dc or ac (other than a tiny stray voltage one could expect being picked up on a long wire run) Thank you for confirming my suspicion that there should be at least a few volts there. My frequency meter died years ago and I have no justification for replacing it. BTW: It is very sad that AT&T now has terrible service, they won't get here until Thursday. When I had a problem two years ago from the time I called until the time they came out and had it all fixed was 90 minutes. I spent more time than that just on the phone. Here's an example of the ADSL startup sequence. https://s22.postimg.cc/56dmtrxlt/DSL...r_Page_148.gif The customer premise end sends "phase reversals every 16ms". Which, roughly translated, is a 60Hz square wave ? Only then does the AT&T end enable its line driver, and send C-TONES. Initially I tried Google searches on "pilot tone" or similar, thinking there was always a signal on the line. It turns out, that the frequency bins in the upstream and downstream have one bin which operates at constant amplitude and is not modulated. And that's a pilot tone that the DSP can use in the frequency domain. But all that stuff only exists when everything is up and operational. Whereas the initiation sequence is much more crude. And starts with silence. it's quite possible your modem "goes first". Â*Â*Â* Paul What made me distrust the AT&T diagnostic was their presumption that their router was bad if they could not communicate with it. Though it could of course be bad, their line could just as well have been open. The second person I talked to understood the logic and I did not have to waste too much time on the phone before she agreed that a tech needed to be sent out. The first person I talked to had me on the phone for an hour running various tests. Oh well, someone will hopefully be here on Thursday. I will probably not check back in here until my service is restored FWIW, I have AT&T uVerse broadband. Each time I've had an isolated outage (meaning one affecting only my service, not like when head-end equipment failed) the problem has been the cables and each time the 'service' people at AT&T determined that the problem was _absolutely_ with my modem. The first time they insisted that I swap modems. After that phone call I took a walk up the street and located the point where the cable had broken. The next time I took the walk _first_ and located the break. The third time I located the point where it had been cut deliberately because the wire tech from the second call had done a sloppy job of installing new cable and put the splice in a more convenient location at head height on the pole which somebody decided would be entertaining to rip out. Makes me wonder what different sectors of their repair department think of one another. |
#10
|
|||
|
|||
AT&T Broadband ? Resolved
On 08/25/2018 05:59 AM, philo wrote:
My service went out and AT&T ran a diagnostic and said my router went out and they would send a new one. While waiting I decided to try my router at a neighbor's house who also has AT&T broadband and it worked OK there so I called them back and they will eventually send a tech out to repair the line. At the wires coming into my house I only got a reading of 2mv ac I know back in the days of landline and DSL the voltage should have been 48vdc as best as I recall...however I don't know what a normal voltage would be for broadband. Anyone here have that knowledge? Thanks Fortunately I can tether my machine to my smartphone to post this. AT&T got here and checked my line all good. The previous tech who was here 18 months ago replaced the router only and the guy who was here said the power supply (with has a built in UPS) is not compatible with it even though it had been working previously. At any rate he replaced the router and it's DC supply and all is good |
|
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Broadband......................... | [email protected] | Printers | 0 | March 20th 08 09:42 AM |
broadband or dsl | rc | Compaq Servers | 3 | August 12th 04 05:18 PM |
Broadband Set up | Matt Newman | Homebuilt PC's | 11 | June 3rd 04 12:59 AM |
broadband | 123xxxxx | General | 17 | February 27th 04 07:14 PM |
DSL vs Broadband. | [email protected] | Dell Computers | 41 | November 28th 03 06:48 PM |