facts: a) A telephone set connected to the external company phone line does not pick the radio, so the PABX is picking it. b) The radio can be heard at the PABX extensions, with or without the external company phone line connected to the PABX, so it confirms the item (a) above. What about if you connect a PABX extension directly to the PABX (half meter wires)? Some PABX have a high voltage protector gas device installed at the inputs and outputs, it is used to short circuit the line in case of a high voltage discharge in the area, as lightning and all. Some of those devices are different, they are silicon made, and some of them short circuit for good after severe problems. If some of them are in short circuit, they are "grounding" one wire of your phone line and then they turn to be "radio antennas". Phone lines are not "grounded", they are balanced to ground, just to avoid to pickup noise and radio interferences. Disconnect ALL your PABX extensions (at the PABX) except the one with short wires, check the radio noise again. Check the PABX power outlet for correct phase rotation. Facing the power output outlet faceplace with the power pin down, the phase pin would be the top right, the neutral (return) is the top left. An AC Voltmeter should indicate nothing, or a very little AC voltage between Neutral and Ground (less than 1 Vac is ok) and there should be current continuity between Neutral and Ground, but not ZERO Ohms. Some places they short ground and neutral pins right at the receptacle, this is a crime. Ground is ground, not current return path, and should be physically grounded close to your house or installation. There should be NO current on the ground wire, except for safety, or if some device connected is leaking current through motors insulators or something like that. Neutral is the wire that returns current to the power transformer, and should be grounded just close to the transformer pole. If the PABX is small (you never said how many lines and extensions it carries), try to use a power surge protection strip, there are filters inside that can cut off this interference. Just for testing install small value capacitors (1nF or less x 250V) in parallel to the extension wires, and see what happens. Use two capacitor in series in between the extension lines and GROUND the middle connection of the capacitors. Wagner. Leo wrote: > > We have made some trial; > > connecting the phone directly to the line caming fron the telephone > company, > the radio there are not. > > The radio can be listened only on the extentions of the PABX with or > without > the thelephone line connected, using different type of thelephone. > > Seems that the radio is piked up by the PABX itself... > > The grounding of the PABX seems good. > > Ciao > > Leo > > ----- Original Message ----- > > From: "Russell McMahon" > > To: > > Sent: Saturday, February 26, 2000 12:22 PM > > Subject: Re: [OT] Radio over telephone line > > > > > > > > > Radio pickup is often caused by imbalance in the phone line. > > Longitudinal > > > > sisgnals received by the long "aerial" which the phone line becomes > are > > > > converted to differential signals which then enter the phone > circuitry. > > > > > > > > This unbalance can be in the line itself or the connected equipment. > > > > The telephone company SHOULD be able to determine where the fault is. > > > > This normally requires disconnecting the line at your premises unles > > they > > > > have fancu equipment (either a remote line disconnector or "pulse > echo" > > > > equipment. > > > > > > > > IF you can connect a standard telephone to the circuit rather than a > > PABX > > > > you should be able to tell if the problem is still there. If it is > > present > > > > when you use only a telephone and the building's equipment and wiring > > are > > > > disconnecetd it is probably THEIR fault. > > > > > > > > On what basis did they say that the fault was in your equipment and > not > > > > theirs? > > > > > > > > Imbalance is often caused by a leakage to ground from one side of the > > > phone > > > > line. This can be caused by a hole in a cable pair, corrosion or > > spider's > > > > web in a terminal box or water in a cable - and many other things. > > > > > > > > > > > > regards > > > > > > > > > > > > > > > > Russell McMahon > > > > _____________________________ > > > > > > > > >From other worlds - www.easttimor.com > > > > www.sudan.com > > > > > > > > What can one man* do? > > > > Help the hungry at no cost to yourself! > > > > at http://www.thehungersite.com/ > > > > > > > > (* - or woman, child or internet enabled intelligent entity :-)) > > > > > > > > > > > > -----Original Message----- > > > > From: Leo > > > > To: PICLIST@MITVMA.MIT.EDU > > > > Date: Saturday, 26 February 2000 22:54 > > > > Subject: [OT] Radio over telephone line > > > > > > > > > > > > >Hi friends, > > > > > > > > > >starting from some weeks ago I have to listen one radio commercial on > > my > > > > >wired phone as backgroun. > > > > > > > > > >Sometimes is low volume, and sometimes is too high that cover the > other > > > > >person listening/speaching on the phone. > > > > > > > > > >I have asked to the telephone company, bu he say tha is a mine PABX > > > > problem. > > > > > > > > > >I have inserted a toroid with three loop of telephone line near the > > PABX > > > > and > > > > >near the telephone, but the problem remain the same. > > > > > > > > > >Do you have any suggestions? > > > > >Do you can suppose the cause? > > > > >Why before I do not have been the problem? > > > > > > > > > >Thanks > > > > > > > > > >Leo > > > > > > > > > >