Telephone Wiring
Telephone wiring is not complex to work with and is very safe, because of the low voltages involved. The most complex part of installing telephone wiring is complying with the many different defined standards for telephone wiring. It is best to determine which telephone wiring standard is currently in use and conform to that standard.
If you are installing telephone wiring into a new facility, use the EIA/TIA T586A standard.
Get the Wire Into Your Residence
The wire has its source at a telephone company, or telco, central office, and goes through various paths to get into the general vicinity of your home.
Above Ground Wiring
In older neighborhoods and areas that have a high water table, the telephone wiring is above ground. There are telephone poles that distribute phone service wire pairs to residences using an aerial method of connection.
A breakout box is attached to the pole with the main services lines for the area entering in one side, and residential lines running out of the other side. Wires are then ran from the breakout boxes to each neighborhood residence.
Underground Wiring
Modern neighborhoods have telephone wiring that runs underground. Breakout boxes are installed in geographically logical points in the neighborhood before the building of homes has started and then lines are trenched back to the primary distribution can for your neighborhood and to each property. This wiring is just a stub, and needs to be extended to the home once the house is built.
The Residential Network Interface Device
The telephone line from the pole or breakout box terminates on a Network Interface Device, or NID, which is screwed to your home. This device is a gray or tan box about eight inches wide and twelve inches long with two compartments: a customer compartment that has a simple slot headed screw for customer access and a telco compartment controlled by the use of a specialized screw head.
You can open the customer access compartment to check your lines for dial tone, wiring connections and to trace lines coming out of the NID into your home. Most NIDs can handle up to 5 different lines.
Testing Your Phone Lines
Always use a previously tested corded phone for phone line testing.
Pick Up the Phone – The easiest phone service test, is to merely plug a phone into the jack with the proper wire, take the phone off of the hook, and listen for dial tone.
No Dial Tone – If you don’t get a dial tone you probably have a phone line problem. If you have multiple jacks in your home, test each one and if some of the jacks work and others don’t, the wiring fault is between the NID and those specific jacks in your home. If none of the jacks are working, you need to test your phone lines at the NID.
Testing at the NID
Open the customer compartment of your NID and notice that for each phone line installed in your house, there will be a phone jack with a line plugged into it. If you have more than one line, labels on the NID lid should tell you which jack is associated with which phone line or number. To test, disconnect the line from the jack, and plug your corded phone into it. If you have dial tone when you hook up your phone, the wiring fault is in your house. If you don’t then you must call the phone company for repair.
When the Wire Colors Don’t Match
Many phone companies have updated their color standards due to the use of Cat 5 cable for most phone line installs, and in this new standard, green, red, black or yellow wires, have been replaced by white/blue, blue/white, white/orange, and orange/white.
To know how to identify the wire color is a simple matter. The following table will help you understand what colors match.
Function New Color Old Color
Tip 1 Green White/Blue
Ring 1 Red Blue/White
Tip 2 Black White/Orange
Ring 2 Yellow Orange/White
New Telephone Jacks
Installing new telephone jacks in the house is easy, but there are some tools and basic hardware you will need:
Tools:
Drill. It is almost always best to use a cordless drill. A 18V or better variant will give you enough power to drill through masonry and thick wood boards. You will need the drill if you are running new lines between house floors or if you want to conceal the wiring in the wall.
Drill bits. If you are drilling through brick or stone, buy a masonry bit, otherwise a wood bit works well. You may want to use a pilot bit for areas that have restricted space or if you are drilling through rough materials.
Flathead Screwdriver. All wiring blocks use slotted screws for the wire connections and for the jack box mounts.
Fish tape. It is really a godsend for a wiring project, if you already have finished walls in your home.
Cable Test Equipment. If you don’t get dial tone, you will need something to test your lines.
Hardware:
Modular jack boxes with wiring box. If you are installing an entirely new jack, you will need a jack box with a wiring box. You only need a jack box without a wiring box if you are replacing a damaged jack box. You will need one jack box for each new jack you want to install.
Four, six or eight strand telephone wire. Buy four wire flat silver satin telephone wire for any new jacks. Its flexible, can easily be stripped off in locations that require it, and it will keep the wires together.
Corded Phone for Emergencies
Standard corded phones receive all necessary power over the phone line itself, no additional power is required so have a corded phone in your residence just in case your other devices have issues, or for use in emergencies when power is out.
General Reference Information
The information following may help you understand the standards and wire plans in your home. They are merely reference materials to assist you in your planning and diagnostics.
The EIA/TIA 568B Standard for Telephone Wiring
Pin (Jack) Pin (Plug) Color Pair
1 8 White/Orange Tip 2
2 7 Orange Ring 2
3 6 White/Green Tip 3
4 5 Blue Ring 1
5 4 White/Blue Tip 1
6 3 Green Ring 3
7 2 White Brown Tip 4
8 1 Brown Ring 4
The EIA/TIA 568A Standard for Telephone Wiring
Pin (Jack) Pin (Plug) Color Pair
1 8 White/Green Tip 3
2 7 Green Ring 3
3 6 White/Orange Tip 2
4 5 Blue Ring 1
5 4 White/Blue Tip 1
6 3 Orange Ring 2
7 2 White Brown Tip 4
8 1 Brown Ring 4
The USOC (Universal Service Order Code) 8 Wire Standard for Telephone Wiring
Pin (Jack) Pin (Plug) Color Pair
1 8 White/Brown Tip 4
2 7 White/Green Tip 3
3 6 White/Orange Tip 2
4 5 Blue Ring 1
5 4 White/Blue Tip 1
6 3 Orange Ring 2
7 2 Green Ring 3
8 1 Brown Ring 4
The USOC (Universal Service Order Code) 6 Wire Standard for Telephone Wiring
Pin (Jack) Pin (Plug) Color Pair
1 6 White/Green Tip 3
2 5 White/Orange Tip 2
3 4 Blue Ring 1
4 3 White/Blue Tip 1
5 2 Orange Ring 2
6 1 Green Ring 3
The 25 pair Telephone Wiring Standard
Pin (Jack) Pin (Plug) Color Pair
1 50 Blue/White Ring 1
2 49 Orange/White Ring 2
3 48 Green/White Ring 3
4 47 Brown/White Ring 4
5 46 Slate/White Ring 5
6 45 Blue/Red Ring 6
7 44 Orange/Red Ring 7
8 43 Green/Red Ring 8
9 42 Brown/Red Ring 9
10 41 Slate/Red Ring 10
11 40 Blue/Black Ring 11
12 39 Orange/Black Ring 12
13 38 Green/Black Ring 13
14 37 Brown/Black Ring 14
15 36 Slate/Black Ring 15
16 35 Blue/Yellow Ring 16
17 34 Orange/Yellow Ring 17
18 33 Green/Yellow Ring 18
19 32 Brown/Yellow Ring 19
20 31 Slate/Yellow Ring 20
21 30 Blue/Violet Ring 21
22 29 Orange/Violet Ring 22
23 28 Green/Violet Ring 23
24 27 Brown/Violet Ring 24
25 26 Slate/Violet Ring 25
26 25 White/Blue Tip 1
27 24 White/Orange Tip 2
28 23 White/Green Tip 3
29 22 White/Brown Tip 4
30 21 White/Slate Tip 5
31 20 Red/Blue Tip 6
32 19 Red/Orange Tip 7
33 18 Red/Green Tip 8
34 17 Red/Brown Tip 9
35 16 Red/Slate Tip 10
36 15 Black/Blue Tip 11
37 14 Black/Orange Tip 12
38 13 Black/Green Tip 13
39 12 Black/Brown Tip 14
40 11 Black/Slate Tip 15
41 10 Yellow/Blue Tip 16
42 9 Yellow/Orange Tip 17
43 8 Yellow/Green Tip 18
44 7 Yellow/Brown Tip 19
45 6 Yellow/Slate Tip 20
46 5 Violet/Blue Tip 21
47 4 Violet/Orange Tip 22
48 3 Violet/Green Tip 23
49 2 Violet/Brown Tip 24
50 1 Violet/Slate Tip 25
Pin Number Orientation
Pins are always numbers with the tab down.
Pin 1 is the left-most pin.
When looking at a telephone plug, Pin 8 is the right-most pin.
Jacks and Plugs
The plug is the male end of a telephone cable and the jack is the female receptacle in the wall.
Tip and Ring
Tip is the electrically positive wire and Ring is the electrically negative wire.
Additional Reading on Telephone Wiring
