1986 Condo Telephone Wiring. Don't Understand.

Reply

  #1  
Old 06-23-16, 01:04 PM
S
Member
Thread Starter
Join Date: Jan 2006
Location: USA
Posts: 101
Received 0 Votes on 0 Posts
1986 Condo Telephone Wiring. Don't Understand.

I don't understand my telephone wiring. Could someone help me understand what's going on here?

I own a condo built in 1986 on the top floor (3rd floor) of my condo building. It has 2 telephone jacks, one in the kitchen and one in the master bedroom.

I'm trying to understand the wiring. I believe it's what's called "continuous loop", versus the home-run type of wiring.

The kitchen jack has 4 cables coming into it. See photo (ignore the upper right cable, that's something else). One pair of cables comes into the bottom of the workbox, which I believe comes up from the telco box on the outside of the building at ground level. One pair of cables comes into the top of the workbox, which I believe goes to the bedroom jack.

The bedroom jack has one pair of cables coming into the top of the workbox, which I believe comes from the kitchen jack.

I don't undertand how this is wired and why there are 2 pairs of cables. It seems like there would only need to be 1 cable coming up from the telco box into the bottom of the kitchen workbox, then 1 cable going from the kitchen workbox to the bedroom workbox. Not sure I understand why there are 2 of each. Can someone explain to me how this works?


Name:  2016-06-23 14.37.32_rs.jpg
Views: 1406
Size:  29.8 KBName:  2016-06-23 14.40.11_rs.jpg
Views: 845
Size:  34.8 KB
 
  #2  
Old 06-23-16, 02:18 PM
F
Member
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 18,495
Received 36 Votes on 28 Posts
Redundant cabling. It was done that way for a number of possible purposes. The primary reason is in case the occupant wanted two separate telephone "lines" (numbers) in which case each incoming cable would be a separate line/number.

The secondary reason is that back then they used a wall-wart transformer to provide power for the dial light on telephones so equipped. These were the black and yellow conductors. Today dial lights are powered from the telephone line itself.

The third reason is in case the first cable gets damaged in some way there is a spare that can be used.


As to how to wire; you first need to determine which incoming cable has the dial tone from the central office. You can then ignore the second incoming cable. Parallel this incoming cable, matching colors, to one of the cables going to the bedroom and ignore the second cable. On each conductor splice you should add a same-colored pigtail to go to the jack where you match colors or if the jack is marked with a T and R the green wire is connected to T (or tip) with the yellow and black wires ignored.

There ARE alternate wiring plans but this is the most common.
 
  #3  
Old 06-23-16, 02:20 PM
S
Member
Thread Starter
Join Date: Jan 2006
Location: USA
Posts: 101
Received 0 Votes on 0 Posts
Is this what a telephone continuous loop looks like, assuming that's what I have in my condo?

Name:  telco continuous loop.jpg
Views: 1082
Size:  20.7 KB

If so, what's the purpose of the "return" path? Why doesn't it go from Telco to Kitchen to Bedroom, and terminate at the Bedroom?

The cables are cut inside the workboxes, so I assume at one time they were not cut and continuous and would have had the insulation stripped off the individual red/green wires to attach to the screw-down terminals of the jack itself.

So, if this is how it's wired, to disconnect from the telephone company but still have the kitchen and bedroom wired to each other, I would just make sure to not connect BOTH wires coming up through the bottom of the Kitchen workbox?
 
  #4  
Old 06-23-16, 02:24 PM
S
Member
Thread Starter
Join Date: Jan 2006
Location: USA
Posts: 101
Received 0 Votes on 0 Posts
Redundant cabling. It was done that way for a number of possible purposes. The primary reason is in case the occupant wanted two separate telephone "lines" (numbers) in which case each incoming cable would be a separate line/number.
Oh. Then my diagram was incorrect -- I was just taking a guess at what was going on. OK, so then 2 separate cables run from the central office box outside. OK, thanks.
 
  #5  
Old 06-23-16, 04:11 PM
ray2047's Avatar
Member
Join Date: Mar 2006
Location: USA
Posts: 33,583
Received 13 Votes on 11 Posts
This is what I think you have. I have shown only the working cable. The phone would be connected to where the incoming and out going wires are connected. Usually red and green are used. This can either be a "buss run" where it ends at the last jack or a "loop" where the last jack connects back to the NID.

Name:  x.jpg
Views: 836
Size:  12.3 KB
 
  #6  
Old 06-23-16, 04:29 PM
S
Member
Thread Starter
Join Date: Jan 2006
Location: USA
Posts: 101
Received 0 Votes on 0 Posts
Your diagram suggests, and I think user Furd was saying that I probably have (2) bus runs, one for operation and one for redundancy.

This can either be a "buss run" where it ends at the last jack or a loop where the last jack connects back to the NID.
My diagram and assumption is a loop, the last jack (bedroom) looping back the way it came, back through the kitchen jack, then back down to the NID. But I don't know why.

What would be the point of having it loop back to the NID? Would there be some kind of terminator on the free end inside the NID? Would the free end just dangle inside the NID? Would it be punched down to an unused block?
 
  #7  
Old 06-23-16, 04:42 PM
S
Member
Join Date: Oct 2013
Location: USA
Posts: 219
Received 3 Votes on 3 Posts
"So, if this is how it's wired, to disconnect from the telephone company but still have the kitchen and bedroom wired to each other, I would just make sure to not connect BOTH wires coming up through the bottom of the Kitchen workbox?"

Yes, first determine which is from the central office. You could cut a line cord and touch the red/green (or 2 center conductors) to the red & green from the cables until you have dial tone. Mark that one for reference - then connect the others to the red and green of the central office cable and check for dial tone bedroom.

Are you planning to install internet phone service with an ATA (Analog Telephone Adapter)? If yes then leave the central office cable disconnected, and the kitchen and bedroom to each other as you said.
 
  #8  
Old 06-23-16, 04:51 PM
F
Member
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 18,495
Received 36 Votes on 28 Posts
What would be the point of having it loop back to the NID?
Absolutely no point. I have never seen or even heard of such practice with communications cabling. Some countries (Great Britain comes to mind) do this with their POWER wiring.

Would the free end just dangle inside the NID? Would it be punched down to an unused block?
Depends upon if the serving telephone company has what is called a "dedicated plant" system in the field. Dedicated plant has all field wiring connected to specific cable pairs from the jacks in the residence to the main frame in the central office. This allows them to connect or disconnect service at the CO by merely a few computer commands. Older systems required a service tech to actually visit the residence to make the connection between the house and the proper cable pair on the pole or in the wiring vault.
 
  #9  
Old 06-23-16, 04:54 PM
S
Member
Thread Starter
Join Date: Jan 2006
Location: USA
Posts: 101
Received 0 Votes on 0 Posts
Are you planning to install internet phone service with an ATA (Analog Telephone Adapter)? If yes then leave the central office cable disconnected, and the kitchen and bedroom to each other as you said.
I have an OBihai (Google Voice) VOIP adapter, sorta like a MagicJack, which has an 4-conductor analog telephone jack. I want to connect the OBihai into my home phone wiring so that my POTS analog phone in the kitchen and bedroom run through the OBihai for phone service. I use all 4 conductors (red/green, black/yellow) because I have 2-line analog phones and 2 accounts on the OBihai VOIP adapter.

I've done this before, I'm just trying to avoid having a live cable from Verizon connected to the wiring.
 
  #10  
Old 06-23-16, 05:51 PM
ray2047's Avatar
Member
Join Date: Mar 2006
Location: USA
Posts: 33,583
Received 13 Votes on 11 Posts
Then use the cable that has no dial tone. You may need to connect it at any junction boxes between two points in use if it was never connected.
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description: