A little earth ground humor

[Joseph]

Finally every one gets off their butt and adds in their two cents worth, while all can agree that a dog cant be electrocuted from a broken ground.

Never say never. It will be the exception that causes the thing that you never find out. Now please quit bsing and think about retirement. There comes that time for everyone.

[rshayes]

Hello Al,

I found one reference that had a graph comparing the performance of the 300 and 500 type telephone instruments. The loop resistance ranged from zero to 1300 ohms, which represented about a three mile loop. The impedance of a single ringer would be about 7000 ohms from your FCC chart. A party line might have four ringers connected (1750 ohms), working with the series resistance of one side of the line (less than 650 ohms). This would drop the ringer voltage to somewhere near 60 volts.

In the audio range, the line is usually considered to be a transmission line with an impedance between 600 and 900 ohms. The loss from the central office to the subscriber will depend on the wire gauge of the line and the distance to the subscriber. From the comparison graph, it appears that the audio loss for the three mile loop was around 6 db. This was with 26 gauge wire. I suspect rural circuits used larger wire to get longer distances.There would be additional loss if the load impedance in the audio range approaches 900 ohms.

[Chris Smith]

With out this post many things would have remained in the locked closet covered with dust.

Now, its like a contest, every one with their own two cents trying to out bid the other.

And all this information comes forward for all to see, and there is a variety in the systems, many systems.

So who needs a rocking chair, the quitter?

[Joseph]

With out this post many things would have remained in the locked closet covered with dust.

Now, its like a contest, every one with their own two cents trying to out bid the other.

And all this information comes forward for all to see, and there is a variety in the systems, many systems.

So who needs a rocking chair, the quitter?

The key is to know and understand one's limitations. There are different types and levels of retirement. We all make choices like that. It's not quiting, but being more effective at what one does. It may simply involve a modification of focus.

We retire every evening just to wake for the next day's start. Every day is new.

For everyone out there, I recommend appropriate quiet time to reflect on things to try to determine your capabilities, the big picture, and hopefully biggest picture, ultimately.

PS. Chris, please check your private message.

[Robert Reed]

MrAl
In reference to "grounds", however we would want to define this whether being earth ground, chassis ground or whatever, there really isn't a dedicated hot lead in the 48 volt system as the whole package is floating. In other words the negative lead of that supply could be considered 'Hot' if referenced to the positive lead and vice versa. I was wondering about your scope setup when grounding the probe clip to the green lead of telco, which would subsequently tie that lead back to the power lines neutral and ground by virtue of the scopes power cord. Maybe you intentionally floated the scopes power line in these tests by using a non grounded adapter in which case it may have worked OK. However if your scope was attached to power in the conventional way (grounded), it seems as though it would upset the measurments at least for AC. When you make your measurments as you mentioned of each side of the Telco line to ground, let us know your results as this would be good information to chew on.
As a side note here are some of my observations over the years and made at different locations:;
The highest loop resistance I have ever measured was 1350 ohms. These were done on a variety of lines some shared and some were "Dedicated Metalic Pairs" - a term for a line leased solely by a private concern with no other Telco appliances on it. All line resistances are recorded at time of installation for trouble shooting problems in the future and are a matter of accesible record at Telco. If I remember correctly, it was desirable to keep loop resistance below 2000 ohms, I have seen 'Off Hook' voltages as low as 6 VDC but never did any further investigation or calculations on this.
Regarding DC remote systems - The maximum DC telco allowed to be placed on a line was 150 VDC. Insulation resistance being the major concern here.
Regarding tone remote systems - the maximum AC Telco allowed was a level of plus 10Dbm/600 ohm.Crosstalk being the major concern here.
The ringing generators I was familiar with were at each terminating end of a PBX microwave stations phone interconnect panel and injected at that point..So line impedance situations were not an issue here as the out runs were fairly short (1/2 mile and less). The ringing voltage was 90 VAC rms.
Standard line test tones were 1004 hertz at plus 8 Dbm/600 ohm.
Some of these figures go back a number of years and some are fairly recent, so Telco standards may have been modified on some of these at this date.

[dyarker]

"rshayes seems to be saying that those impedances are the min
allowable for a ringer circuit." That would make more sense for that chart.

[Dave Dixon]

I told this story a few years ago on here, but I just have to tell it again. One very damp morning I noticed that my phone was inop. Being the "technician" that I am, I immediately recalled my neighbor planting flowers the previous evening and surmised that she cut the line while digging. Sure enough, the line was only buried a few inches down and was severed.
As I was doing a temporary splice, she came out to apologize and watch me. As I was twisting the wires together in my finest "Western Union" splice, she quit apologizing, and inquired why I didn't seem concerned about getting "electrocuted" (her words). Sure enough, I began to explain that the only thing that might give me a tickle, was if I just happened to receive a phone call at the same instant. WELL, guess who received a phone call in the middle of my sentence? No damage was done to anything but my ego, but it really hurt! I guess the damp ground helped to give me more than the tickle I would have expected.
No chest pounding from me on this topic
Dave

[Robert Reed]

"Now, its like a contest, every one with their own two cents trying to out bid the other."


Oh no, you are mistaken.
We are just a friendly group having a very interesting and knowledgeable discussion. And as such each shared a little bit of knowledge that aided all of us in a leap-frog style fashion.
It is called learning from others and aside from your negative replys, I think the rest of us will walk away from this post having a little more insight on the subject!

[Chris Smith]

Stick to your answers, you will never make it in the psychology arena.

You can try and label anything you want, you can even convince your self you think you know what’s going on, but change the facts you cant do.

You haven’t yet distinguished the differences between the cliques, the tag teams, and the bait and switch gang yet, in fact I doubt you even see them.

But you do know when the story will make it onto the burner, right after the thick stuff starts to float.

[jollyrgr]

My Dad was an electrical engineer and got his start working for Northern Electric. He told me that in the old phones, the ringer has a separate ground. I think that the color of this wire was yellow.

Old phones DID use the yellow wire for the ringer. But this was not quite a GROUND wire; but yet it was. (I'll try and explain without getting too goofy.) According to an "old timer" in the phone industry there was a good reason for this separate yellow wire scheme. Modern and single line phone systems and modern phones pick up their ring signal across the TIP and RING wires. This is the TYPICAL way of giving a ring signal. (NOTE: RING in TIP and RING does not designate "ringing" signal; this is the RING connector on the phono plug.)

On these old phones the yellow wire would connect to one side of the bell circuit (a coil and a cap in series). The other side of the bell cirucit was connected internally to EITHER L1 or L2 or the TIP and RING. (I may have the designation backward as to if L1 goes to TIP or not.) At the phone junction box of a SINGLE phone line you tied the yellow wire to the opposite colored wire than the one inside the phone. Let's say you did not know what wire the internal bell circuit went to. You would tie it to the red wire inside the junction box and call the phone. If the phone did not ring, you tied it to the green wire.

In any case in the days of the "phone police" you could only have one phone or you had to pay for each extra phone (even on the same line). To prevent the phone company from finding out if you had more than one phone, you simply did not connect the yellow wire. This way the phone police did not see the extra impedance on your phone line.

But WHY was this goofy arrangement done in the first place? This was a hold over from PARTY LINE days. Apparently the ring signal can be sent down the TIP and RING, or the TIP and GROUND, or the RING and GROUND. Thus when you had a number of people on a PARTY line you did not have to ring EVERYONE's phone! You could ring the TIP PARTY or the RING PARTY. Thus instead of having eveyone put up with hearing a ring, only 50% of those on the party line heard the ring. In the case of the party line, the yellow wire went to a ground at the juction box.

[Chris Smith]

Back then they didn’t have the two wire hybrid systems of today to sort out all of the 4 wires.

The bell was the obvious draw in power and they didn’t want to have to add in more power, you got what you paid for and more phones meant more “Ringer Equivalenceâ€

[jollyrgr]

I told this story a few years ago on here, but I just have to tell it again. One very damp morning I noticed that my phone was inop. Being the "technician" that I am, I immediately recalled my neighbor planting flowers the previous evening and surmised that she cut the line while digging. Sure enough, the line was only buried a few inches down and was severed.
{SNIP}
Dave

This reminds me, I have to fix my parents' phone wires. Back last winter (when it was icy and hovering around zero for several days) my mom noticed poping and static on the line. She of course calls me. The buzz, pops, and sizzle immediately told me that there was water on the wires. The weather had been freezing rain, sleet, etc. but this had never been a problem in the past. I asked if either her or dad had been moving anything around by the phone service box outside or if they saw anyone working on the phone junction box in the back yard. She said NO but that she HAD seen a rabbit living under the bushes next to the phone box. Being night she didn't want to go out in the cold and rain to look at it.

The next morning she went out to look. The wire leading from the phone box into the basement of the house, about a six inch piece of four conductor phone wire, had been chewed on by the rabbit. (This wire had been exposed for 17 years and worked fine until the rabbit found it.) I told her to dry it off and try to protect it by putting something up against it. Well my dad went out and put electrical tape around the wire. This resulted in a complete short and no phone service. Now I get a call from her cell phone, how do they fix this problem? My solution was to take a cordless phone outside and take off the tape. Wiggle the wire until it sounded okay on the cordless phone. Problem solved until I could get out there.

I go out there that weekend. Remember how I said the temperatures were very cold? The wire had been chewed and was getting worse as the rabbit would not give up! In just above zero (F) weather I'm trying to splice phone wire. No luck rescuing the wire already there. I grab a scrap piece of thermostat (or speaker??) wire and tie in a new connection to about a two inch pig tail sticking out of the wall. I figured this would be good until spring. Well OOOOOOOPS!!!!!! I forgot all about having to fix this. On the positive side my half arse splice has been working since last January, and the rabbit does not like the wire I used.

[Chris Smith]

Up here we have above ground and below ground connection.

The above ground wires seems to be for creeks and rivers, while the below ground is the 20 year sealed and guaranteed lines.

Every time the wind blows, and you have a creek along your way, the ghosts appear in the signal, the web is slowed to a snails pace, [crackle] and the lines simply go down.

Dial up just doesn’t work at these error rates.

[Robert Reed]

"Back then they didn’t have the two wire hybrid systems of today to sort out all of the 4 wires. "

Then give us a detailed and clear explanation of how two way conversation could have occured at the same time on a two wire line.

[Chris Smith]

I dont care about the price of TEA in china.


If you dont know already about the ringer, the ground, the yellow wire, the black wire, etc.,....,....then Pick up a book, and dont waste today's time here.

Ancient news.

There are two cents out there, and then some....

Just one of the books I have is 1978, ancient, diaper material for others.