25-pair cable color codes
for punch-down blocks & connectors

25-pair cable color codes<br>for punch-down blocks & connectors
  • Electrical devices -- including phones, light bulbs, bicycle horns, hi-fi speakers and air conditioners -- generally use a pair of wires (two wires working together) to complete an electric circuit from and back to a source of power, signal or data.
  • Multi-pair phone and data wire uses an industry-standard color code to distinguish one pair from the others, and to identify the wires within a pair. Each wire usually has a base color and a contrasting stripe, and the other wire in the pair has the opposite colors.
  • The first pair of wires in a multi-pair cable usually has a white wire with blue stripes, and a blue wire with white stripes. There are codes for 25 different pairs.
  • The first wire in a pair is traditionally identified as "tip" and has positive voltage. The second wire in a pair is called "ring" and is negative. The tip and ring terminology refers to the construction of the plugs used in old-fashioned "Lily Tomlin" switchboards.
  • What normal people describe as "gray" is traditionally identified as "slate" in the phone business, to avoid confusion caused by a "GR" abbreviation which could be either green or gray.
  • What most people describe as "purple," is traditionally called "violet" in the phone business. We don't know why "PU" isn't used for purple. Maybe people think "PU" smells bad.
  • Sometimes, half of a wire pair is solid, not striped. For example, you might find a solid blue wire mated with a white wire that has blue stripes.
  • You may also find wire without stripes, such as solid white mated with solid blue (common in underground cable). This can be a major PITA to deal with as pairs get untwisted, and you're not sure which white wire belongs with which colored wire.
  • Older commonly-used phone wire, known as "quad" or "D station wire" had four wires (green, red, black, yellow) in an outer jacket, but not constructed in pairs. This type of wire is considered obsolete today, and should not be used.
  • When phone cables have more than 25 pairs, each group of 25 pairs is wrapped with distinctive colored nylon thread, in a binder group.
  • Although there are fifty-different-colored wires in a common 25-pair cable, there are actually only ten colors used, five for bases and five for stripes. Beginning phone guys generally carry a chart, but eventually memorize the code.
  • Here's a mnemonic device that may help you remember:

    Base colors: White, Red, Black, Yellow, Violet -- "Women Really Believe You're (a) Virgin."

    Stripes: Blue, Orange, Green, Brown, Slate -- "Big Old Guys Bowl Saturday."

  • Be careful, because three colors (blue, black and brown) begin with "B." Wiring diagrams often use BL for blue, BK for black and BR for brown.

  • Base color/
    Stripe color
    Polarity
    (Tip is
    Positive)
    Pair # Pin # in
    25-pair
    "Amphenol"
    Connector
    Row # in
    66 or 110
    Punch-down
    Block
    White/Blue
    Blue/White
    Tip 1
    Ring 1
    Pair 1 26
    1
    1
    2
    White/Orange
    Orange/White
    Tip 2
    Ring 2
    Pair 2 27
    2
    3
    4
    White/Green
    Green/White
    Tip 3
    Ring 3
    Pair 3 28
    3
    5
    6
    White/Brown
    Brown/White
    Tip 4
    Ring 4
    Pair 4 29
    4
    7
    8
    White/Slate
    Slate/White
    Tip 5
    Ring 5
    Pair 5 30
    5
    9
    10
    Red/Blue
    Blue/Red
    Tip 6
    Ring 6
    Pair 6 31
    6
    11
    12
    Red/Orange
    Orange/Red
    Tip 7
    Ring 7
    Pair 7 32
    7
    13
    14
    Red/Green
    Green/Red
    Tip 8
    Ring 8
    Pair 8 33
    8
    15
    16
    Red/Brown
    Brown/Red
    Tip 9
    Ring 9
    Pair 9 34
    9
    17
    18
    Red/Slate
    Slate/Red
    Tip 10
    Ring 10
    Pair 10 35
    10
    19
    20
    Black/Blue
    Blue/Black
    Tip 11
    Ring 11
    Pair 11 36
    11
    21
    22
    Black/Orange
    Orange/Black
    Tip 12
    Ring 12
    Pair 12 37
    12
    23
    24
    Black/Green
    Green/Black
    Tip 13
    Ring 13
    Pair 13 38
    13
    25
    26
    Black/Brown
    Brown/Black
    Tip 14
    Ring 14
    Pair 14 39
    14
    27
    28
    Black/Slate
    Slate/Black
    Tip 15
    Ring 15
    Pair 15 40
    15
    29
    30
    Yellow/Blue
    Blue/Yellow
    Tip 16
    Ring 16
    Pair 16 41
    16
    31
    32
    Yellow/Orange
    Orange/Yellow
    Tip 17
    Ring 17
    Pair 17 42
    17
    33
    34
    Yellow/Green
    Green/Yellow
    Tip 18
    Ring 18
    Pair 18 43
    18
    35
    36
    Yellow/Brown
    Brown/Yellow
    Tip 19
    Ring 19
    Pair 19 44
    19
    37
    38
    Yellow/Slate
    Slate/Yellow
    Tip 20
    Ring 20
    Pair 20 45
    20
    39
    40
    Violet/Blue
    Blue/Violet
    Tip 21
    Ring 21
    Pair 21 46
    21
    41
    42
    Violet/Orange
    Orange/Violet
    Tip 22
    Ring 22
    Pair 22 47
    22
    43
    44
    Violet/Green
    Green/Violet
    Tip 23
    Ring 23
    Pair 23 48
    23
    45
    46
    Violet/Brown
    Brown/Violet
    Tip 24
    Ring 24
    Pair 24 49
    24
    47
    48
    Violet/Slate
    Slate/Violet
    Tip 25
    Ring 25
    Pair 25 50
    25
    49
    50