This topic is a spinoff from a post in the pictures of ugly cabling topic.

I have a couple of pieces of lead jacketed cable. The conductors have pulp insulation.

One thing I've noticed is that the color code on the insulation is just about impossible to decipher.

Bill mentioned that there was no color code (at least a code like we know today).

How did field technicians work with this type of cable if there were no base/stripe colors imprinted on the insulation? It does appear that some of the insulation is dyed.

I used a rotary pipe cutter to cut the lead jacket. It does a good job...as long as I don't tighten down too tightly on the cable.

If the cable is more than 100 pairs, then it is laid up in groups of 50 pairs. Each group is made up of pairs that are all colored the same. For instance, natural (white-ish) is the tip, and the other color is the ring.

When splicing, "random" splices are made, making sure that at each intermediate splice along a run, the groups (but not the individual pairs within the group) are mated properly. At these splices, all 50 pairs in a group are mated with 50 pairs of the equivalent group in the adjoining section. At the CO end, and the terminal end, a talk pair is established, and a person at each end wearing a headset determines the individual pairs, by sending tone back and forth. That is when the numbered pair code is created.

As each pair is identified, the splicer pushes the pair of wires through one of 50 numbered eighth-inch holes in a linen tag, called a "board." This process is called "boarding the group."

The groups:

When the sheath is cut off, and housekeeping is taken care of (bonding, grounding, wrapping the "choke" of the cable with tape to prevent abrasion, separating and identifying the groups of 50 pairs, etc) the splicer uses a code that is created by the colors of the groups.

Holding the end of the cut cable, you will see that the groups of 50 pairs are all natural (white) and a color. But, there is only one group that is colored with white/green pairs, in each concentric ring of groups. That group is counted as number 1.

The adjacent groups are labelled with numbered tags or tape, or colored tie-wraps, as follows:

If you are facing the Central Office, the groups are numbered COunter-clockwise. If you are facing the "Block" (field) you count Clock-wise. The mnemonics are "CO = COunter" and "Clock to the Block".

If there are so many pairs that the cable has more than one layer of 50-pair groups, then you start over, looking for the one white/green group in the next layer inside. The clock/counter clock counting is the same in every layer.

Because pulp cable is prone to faults during manufacture, the factory tests each pair, and attaches a tag that indicates how many faults (generally, opens) that exist and in which groups they are. The maximum allowable percentage of faults is 1% per 900 feet of cable.

There are "interstitial" pairs that are laid up, singly, in the spaces (interstices) between the groups. These pairs are colored in strange but distinctive ways: red/black, yellow/black, red/yellow, green/black, etc. They are spliced one-for-one at each intermediate splice, and are used during repairs to by-pass defective pairs found after the cable is in service. Generally, there is one interstitial pair per 100 pairs. A 600-pair cable, therefore, will actually contain 606 pairs. This policy is also used in PIC cable of large counts, generally 600-pairs or bigger. There are uniquely-colored PIC pairs wound into the cable that are used the same way as the ones in the pulp cable.

During routine maintenance, a tone is sent from the nearest terminal or frame, or PIC splice to determine the code. If a cable failure occurs, a team of splicers sets up as if they are installing a new cable, using talk wires, and tone is sent to identify the pairs.

Pair number 1 is in the center of the cable, along with his friends, pairs 2 - 50. As you go out towards the surface of the cable, the pair count increases. This is because in the field, the terminal furthest from the CO has the lowest numbered pair count. As the cable size decreases along a run, the outer groups of pairs drop off and feed terminals, and the center of the cable "keeps on going" so to speak.

For further reference, see BSP's in the 632-xxx-xxx series.

Only thing I can add to what Arthur has posted is you only worried about the actual pair on the ends of the count, in the middle all you cared about was the groups were spliced group to group. This is on new splices, should a working "hot" cable get cut than all pairs had to be toned, but you knew which group to look for the tone.

I think my pieces are 25 pair...but I can dig them out for a quick count.

Reading Arthur's description of how technicians worked with this cabling...I realize how lucky I am not to have to wrestle with it. Having conductors clearly marked with distinct base/stripe coloration within colored binders takes away part of the work needed to root out a specific pair during initial installation.

I am surprised to read about the elevated failure count. Is that due to the nature of the pulp insulation itself...along with the fabric sleeves that were used when conductors were joined (soldered) together?

Installers didn't have to worry about it. They worked in the terminals where the count was broken out. Remember back then it was all binding post to the installers, not cable pairs.

Fascinating stuff.

You young pups missed out on the troubleshooting wet splices with a Megger. Crank until it smokes, repair burnt area, repeat as needed.

Thank goodness for that!!!

I can only imagine what a full reel of cable...even 25 pair...must have weighed.

Click

A BSP is always preferable to the fading memories of an old telephone man. Click the above link for the real story. Scroll down and hit "VIEW".

I dug out one of the pieces of 25 pair cable. This cable was found in a riser space on the floor that Global Crossing used to lease.

The cable jacket is dark gray in color. Half of the insulators are neutral in color while the other half are striped. The stripes are very tight, but fairly clear. The insulation actually feels like cloth.

Now the old mains into the building basement were the bland colored pulp.

Checking out the link that Arthur posted.

We used a burn box. They always made sure the count was clear before burning, that is why you always checked in before opening a splice and checked out when done for the day, so you didn't get zapped.

One other thing not mentioned was the lead pulp and paper cable were maintained under pressure to keep moisture out. In later years they didn't maintain the air pressure they said it was cheaper to shoot the wets than maintain the pressure. Not sure I agree, but that was the stand by upper management, don't think they really cared much about customer outages of short duration.

There weren't too many bad pairs, but you spliced through the spares just in case. As far as the soldered connections and cotton sleeves, that was reserved for toll cables when I started splicing, exchange cables we just used beans.

The BSP that Arthur linked mentions that Western Electric painted the ends of the cables and capped the ends of any defective pairs. I'm wondering if what Bill said...about the sleeves and beans...was observed across the entire Bell System.

Yep..I can't remember the last time I saw a nitrogen bottle sitting out at a site. Used to be a regular occurence.

I'm still surprised at how many I see chained to a telephone pole around here. Most look like they haven't been touched in decades.

Probably abandoned in place.

As a young guy on the line crew, I sometimes got to help our splicer with lead cable. I remember cables with white and red conductors. There was one pair of white and black, which we used for a talk pair. Tone sent, then found with an inductive pickup, then applied a short to be read at the toner end to confirm the right pair, then spliced. Look for next pair.

When finished, the lead sleeve preparation and installation was quite a procedure too. This was in GTE territory.

Jim

When servicing buildings...as opposed to interoffice cables...was there a certain pair count that field techs worked with more often than not? Say 200 pair...500 pair?

It was entirely dependent upon the engineers' vision of how many circuits might be needed. A typical residential block in an inner city would have a 600-pair feeder cable, distributed to all the little buildings via block cables of 25 to 100 pair capacity.

A high-rise office building might have multiple 1200, 2400, or 3600 pair cables to service the high-density office spaces.

Often, when a building occupancy was changed from, say, a loft building doing light manufacturing, fed with 100 pairs, to offices, the company would blow out the side of the nearest manhole, install a 600-pair cable, and run new risers to the floors.

Once the lead cable was terminated within a building, is that where/when service to the various floors/suites was usually transitioned over to PVC jacketed multi-pair cables?

There was a period of time before plastic was invented, during which the only cable jacket was lead.

Most "pre-war" (between WW1 and WW2) city buildings had lead/pulp house cables (risers from the basement to floors) and local cables (horizontal on a particular floor.)

Later, there was a transition to PIC in feeders, risers, and horizontal cabling.

There are still many millions of feet of lead cable still in service, in buildings, in the ground, in ducts, and in the air.
The people who knew how to trouble-shoot and repair them are all pensioned off, along with the tools and knowledge. The phone companies are relying on a business model of going out of business before they need to replace the cables. Verizon's Chairman said that a few years ago, when he announced that copper phone service was dead and his company was now focusing on cellular service.

The "mechanics" that were responsible for maintaining the lead around here have dwindled down to one craftsman and a helper for all of Western PA. From time to time, a crew can be seen removing lead from poles, but as Arthur stated, there are millions of feet of lead in manholes and in older buildings. Here in western PA, the rule of thumb is lead feeder from the street transitioned to PIC in 80% of the buildings for riser cables.

There are some old buildings where the lead is still in use. This usually causes a lot of concern for the architects when remodeling, but, never given a second thought when the circuits work in the newly remodeled spaces. One day, when the last "mechanic" is gone, there will be a day of reckoning. If Verizon is smart, they will do like they did for CO change outs and hire responsible contractors to remove and replace the lead with PIC....but, whoever said Verizon was smart?

Rcaman

OK a little off track, but not much. I get a kick when I see the phone guy's all dressed up in their paper suits, hats, booties and mask to work lead. Guess I won't last much longer with all that lead in my system, maybe I'll come back as an anchor.

Much has changed about how people view lead since these cables were installed. Leaded gasoline is gone as is lead covered cables. Maybe the day may come when at&t and Verizon will flush cut dead cable on a case by case basis and dispose of it

Oh yeah, I know Paul, I still get a kick out of it when I see them all suited up. Of course I don't raz them...much.

In the early 80's I was an OSP Engineer. I still remember seeing, on the records, wooden ducts in the underground in Leavenworth, KS. I guess lead cable was no problem for the wood, becase it was encased in dirt, but still, thats a lot of weight.

My union (Local 3 IBEW) runs a class in High Voltage splicing. They used to run it down the hall from where the Telecom/Datacom classes were given and I used to BS with their instructors.

Electrical HV is or, if they've given it up, still has a significant amount of Lead cable and Lead wiping etc is still taught by these guys. I mentioned Lead telephone cable and they said that one of the modules for many years was a Telephone cable but a few years earlier (probably 10 years ago by now) it was phased out because there had been no call for it for several years.

I know Verizon still has lead around in some of the old situations, but they've been removing it whenever they work on it.

Sam

I remember the first time I helped remove an aerial lead cable. It was a short block long. We didn't know what we were doing and it was before all the safety requirements. We cut both ends of lead, then removed the three bolt clamps from the pole attachment. When we cut the support strand, it fell to the ground like it was shot from a missile launcher! _lots_ of weight there!

Jim

I sure wouldn't want to have a heavy hunk of cable land on my head...or...a reel of it being dropped on my foot!

Health concerns aside, is lead jacketed cable more resistant to
weather and infestation when compared to modern equivalents?