Yep, the pairs should be Yellow - Black, and Green - Red. The Green - Red pair is usually used first, then the Yellow - Black pair is used for a second line or for the low level ac used to light the old princess phones. The fact that ac could be carried on the adjacent pair without noticeable hum says something about the hum rejection of the twisted pair construction. But the wire he used for direct burial will not last. In fact, if a mole has already nibbled or it or if it was damaged during installation, that may be the source of your hum. Try using the other pair and see if the hum level changes for starters.
----- Original Message ----- To: "Multiple recipients of list CHIPDIR-L" <[EMAIL PROTECTED]> Sent: Sunday, October 06, 2002 3:28 PM > Hi all responding, > > When the cable is 4 wire, it is likely that there are 2 twisted pairs > in it. If the landlord used 2 wires from different pairs the balance > will be bad. Look at the cable and see whether there is used one > twisted pair. When u have luck this can save u the digging! > > Regards, Harry > > > The cable itself is probably the problem. I'm no phone expert, but I install > > phones once a year, for a convention. The best phone wire is twisted pair > > single strand. If your landlord used four wire multi strand, not only will > > you have a hum, but also some loss over the distance. Can the wire be changed? > > Declan Moriarty > > > > Was it Jeremy N. E. Proffitt who wrote on Sunday 06 October 2002 14:38: > > > It is an extension to my landlord's shop. The hum didn't exist till after > > > installation, they used standard four wire phone cable - not sheilded. My > > > landlord installed this line himself. If you are in the shop and turn on > > > the compressor or table saw, the hum gets worse. Is there a filter I can > > > add or something? > > > > > > Cheers > > > Jeremy > > > ----- Original Message ----- > > > From: Syd H. Levine > > > To: Multiple recipients of list CHIPDIR-L > > > Sent: Saturday, October 05, 2002 11:48 PM > > > Subject: Re: Eliminating 60 Cycle hum on phone line > > > > > > > > > How do you know that is the direct cause? Buried phone lines are > > > normally shielded, and power line hum is usually related to a ground fault > > > of one kind or another. Another common cause is rodent damage in pedestals > > > that can make those spots act like a semiconductor and pick up all sorts of > > > noise. Did the hum get worse over time? Did it start suddenly? Has it > > > existed since the installation? Who was the wise guy that put em in the > > > same trench? Is this a telco installation, or private? ----- Original > > > Message ----- > > > From: Jeremy N. E. Proffitt > > > To: Multiple recipients of list CHIPDIR-L > > > Sent: Sunday, October 06, 2002 2:23 AM > > > Subject: Eliminating 60 Cycle hum on phone line > > > > > > > > > Anybody out there have any good ideas on how to eliminate a 60 cycle > > > hum from a telephone line. The hum is directly related to the phone wire > > > being run with 500 feet of power cable in the same trench. > > > > > > Any ideas would be appricated. > > > > > > Thanks > > > Jeremy > > -- > Author: H.C. Croon > INET: [EMAIL PROTECTED] > > Fat City Network Services -- 858-538-5051 http://www.fatcity.com > San Diego, California -- Mailing list and web hosting services > --------------------------------------------------------------------- > To REMOVE yourself from this mailing list, send an E-Mail message > to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in > the message BODY, include a line containing: UNSUB CHIPDIR-L > (or the name of mailing list you want to be removed from). You may > also send the HELP command for other information (like subscribing). -- Author: Syd H. Levine INET: [EMAIL PROTECTED] Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB CHIPDIR-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
