If are terminating a 25-pair Amphenol Connector (RJ21X) on a M-66 punch down block, you have to understand the full NEMA (National Electrical Manufacturers Association) color-coding scheme.
This design uses paired colors (primary and secondary) to identify a pair of conductors. One conductor is the primary color with a stripe of the secondary color and the other conductor of the pair is the secondary color with a stripe of the primary.
For a 25-pair color, the full table of colors is:
Primary Secondary
White Blue
Red Orange
Black Green
Yellow Brown
Purple/Violet Slate
You can buy a m-66 Punch Down block with a 50-Pin Amphenol Conector to elminate
the need to punch down the Channel Bank side,
and just punch down the FXS Station sets and CO/FXO Lines
T1 50-Pin Amphenol Connector Pinouts -> 66 Punch Down Block
Card Amp50 T/R Primary/Secondary 66 ‘M’ PunchDown Block Side ‘A’
Channel PIN Signal WirePair Color RowNumber
1 1 RING 1 Blue/White 1
1 26 TIP 1 White/Blue 2
2 2 RING 2 Orange/White 3
2 27 TIP 2 White/Orange 4
3 3 RING 3 Green/White 5
3 28 TIP 3 White/Green 6
4 4 RING 4 Brown/White 7
4 29 TIP 4 White/Brown 8
5 5 RING 5 Slate/White 9
5 30 TIP 5 White/Slate 10
6 6 RING 6 Blue/Red 11
6 31 TIP 6 Red/Blue 12
7 7 RING 7 Orange/Red 13
7 32 TIP 7 Red/Orange 14
8 8 RING 8 Green/Red 15
8 33 TIP 8 Red/Green 16
9 9 RING 9 Brown/Red 17
9 34 TIP 9 Red/Brown 18
10 10 RING 10 Slate/Red 19
10 35 TIP 10 Red/Slate 20
11 11 RING 11 Blue/Black 21
11 36 TIP 11 Black/Blue 22
12 12 RING 12 Orange/Black 23
12 37 TIP 12 Black/Orange 24
13 13 RING 13 Green/Black 25
13 38 TIP 13 Black/Green 26
14 14 RING 14 Brown/Black 27
14 39 TIP 14 Black/Brown 28
15 15 RING 15 Slate/Black 29
15 40 TIP 15 Black/Slate 30
16 16 RING 16 Blue/Yellow 31
16 41 TIP 16 Yellow/Blue 32
17 17 RING 17 Orange/Yellow 33
17 42 TIP 17 Yellow/Orange 34
18 18 RING 18 Green/Yellow 35
18 43 TIP 18 Yellow/Green 36
19 19 RING 19 Brown/Yellow 37
19 44 TIP 19 Yellow/Brown 38
20 20 RING 20 Slate/Yellow 39
20 45 TIP 20 Yellow/Slate 40
21 21 RING 21 Blue/Purple 41
21 46 TIP 21 Purple/Blue 42
22 22 RING 22 Orange/Purple 43
22 47 TIP 22 Purple/Orange 44
23 23 RING 23 Green/Purple 45
23 48 TIP 23 Purple/Green 46
24 24 RING 24 Brown/Purple 47
24 49 TIP 24 Purple/Brown 48
25 Not Used Slate/Purple
25 50 Not Used Purple/Slate
DigiumT1 -> RJ-48(F) X-Over
Digium T1 Card Channel Bank RJ-48(F)
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Pin Pair# T/R Color Pin T/R
1 2 T white/orange 4 R1
2 2 R orange/white 5 T
4 1 T blue/white 1 R
5 1 T white/blue 2 T1
3 Not assigned
6 Not assigned
7 Not assigned
8 Not assigned
See also: crossover T1 cable
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