Wiring Information

 

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Wiring Information

WIRING MODERN TELEPHONE SOCKETS (LJU's)

Fact-file: D.I.Y. extension wiring was introduced in 1986

Wiring Diagram for Master & Extension Telephone Sockets

Pin Use Master Socket   1st Secondary Socket 2nd Secondary Socket 3rd Secondary Socket etc. Pin
1 Not used § Green/White Green/White Green/White Green/White 1
2 'B' wire (-50V to earth) Blue/White Blue/White Blue/White Blue/White 2
3 Bell wire Orange/White Orange/White Orange/White Orange/White 3
4 Earth (PABX use only) White/Orange White/Orange White/Orange White/Orange 4
5 'A' wire (0V to earth)  White/Blue White/Blue White/Blue White/Blue 5
6 Not used § White/Green White/Green White/Green White/Green 6
 
Notes: A domestic single line telephone installation will have one master socket which is provided by the service provider (B.T., cable company etc.). A master socket contains a 1.8µF capacitor to pass ringing current to the telephones, a surge arrestor 11A or 26A to suppress high voltage spikes etc. and a 470k ohm resistor for testing purposes. Additional secondary sockets are wired off the master as shown above, the colour codes shown are the standard, but may differ in some existing installations.
 

In recent years NTE5 or CTE5 Lineboxes are fitted in place of master sockets, these have a removable (lower half) panel which house the terminals to connect wiring to the secondary sockets. § Terminal pins 1 and 6 may be absent on some versions of C/NTE5, but these connections are not normally used anyway.

NTE5 Linebox wiring instructions

On older installations (pre-1980) cream or grey cables were used. They contained conductors coloured blue to pin 2, orange to pin 5, brown to pin 3 and green to pin 4 (if used), on some conversions green was used for pin 3 and brown for pin 4. 
Additional Bells are wired between pin 3 (orange/white) and pin 5 (white/blue).
 
For further information on telephone sockets including NTE5 with ADSL faceplate visit the Line Jacks page.
BT NTE5 Linebox BT NTE5 Linebox LJU2/1A Master LJU LJU2/1A Master LJU LJU2 Secondary LJU LJU2 Secondary LJU
NTE5 Linebox

LJU2 Master Socket

LJU2 Secondary Socket
 

Instructions on how to convert old hard wired telephones to new-style wiring
 

 BT Line Cord fitted with plug 431A (4-way) or 631A (6-way)

BT Line Cord
Line Cord Type No: Length Number of Conductors
4/500 150/3000/5000 mm Four
4/501 420 mm Four
4/502 3000 mm Four
4/503 200 mm Four
4/504 3000 mm Four
4/505 150 mm Four
6/500 3000 mm Six
6/502 420/3000/5000 mm Six

6/505

 570 mm Six

 BT Handset Cord fitted with plug 430A

BT Handset Cord

BT Type No. 4/503

Wiring Faults
  Problem Solution
  •  
 Phone ringing continuously Terminals 2 and 5 swapped between sockets (2 at one socket connected to 5 on another and vice versa)
  •  
 No ringing Terminal 3 disconnected
  •  
 Ringing but no speech (or very poor speech) and can't dial out. Wire between terminals 2 or 5  broken.
  •  
 Very poor speech quality, possibly poor bell Terminal 3 and 2 or 3 and 5 transposed

Wiring Colours for CW1311 Internal 4/6 Way Telephone Cordage 

normally used to connect between telephones & line jacks 431A & 631A

Contact 1 Black   system phones 6-way only
Contact 2  White   'A' wire 4 & 6-way
Contact 3 Green   Earth wire 4 & 6-way
Contact 4 Blue   Bell wire 4 & 6-way
Contact 5 Red   'B' wire 4 & 6-way
Contact 6 Orange   system phones 6-way only

ISDN Wiring for RJ-45 Sockets
Contact 1 White/Orange Contact 5 White/Blue
Contact 2  Orange/White Contact 6 Green/White
Contact 3 White/Green Contact 7 White/Brown
Contact 4 Blue/White Contact 8 Brown/White

Wiring Colours for CW1308 Internal Telephone Cable
Pair No. 'A' wire 'B' wire
1 White/Blue Blue/White
2 White/Orange Orange/White
3 White/Green Green/White
4 White/Brown Brown/White
5 White/Grey Grey/White
6 Red/Blue Blue/Red
7 Red/Orange Orange/Red
8 Red/Green Green/Red
9 Red/Brown Brown/Red
10 Red/Grey Grey/Red
11 Black/Blue Blue/Black
12 Black/Orange Orange/Black
13 Black/Green Green/Black
14 Black/Brown Brown/Black
15 Black/Grey Grey/Black
16 Yellow/Blue Blue/Yellow
17 Yellow/Orange Orange/Yellow
18 Yellow/Green Green/Yellow
19 Yellow/Brown Brown/Yellow
20 Yellow/Grey Grey/Yellow
21 Violet/Blue Blue/Violet
22 Violet/Orange Orange/Violet
23 Violet/Green Green/Violet
24 Violet/Brown Brown/Violet
25 Violet/Grey Grey/Violet
26 Pink/Blue Blue/Pink
27 Pink/Orange Orange/Pink
28 Pink/Green Green/Pink
29 Pink/Brown Brown/Pink
30 Pink/Grey Grey/Pink

Note: The first colour is the base colour & the second colour is the trace colour

For further technical information on telephone cables, see the Belden web site

Wiring Colours for CW1293 Internal Telephone Cable

CW1308 is now more commonly used

Pair No. 'A' wire 'B' wire
1 White Blue
2 White Orange
3 White Green
4 White Brown
5 White Grey
6 Red Blue
7 Red Orange
8 Red Green
9 Red Brown
10 Red Grey
11 Black Blue
12 Black Orange
13 Black Green
14 Black Brown
15 Black Grey
16 Yellow Blue
17 Yellow Orange
18 Yellow Green
19 Yellow Brown
20 Yellow Grey
21 White/Blue Blue
22 White/Blue Orange
23 White/Blue Green
24 White/Blue Brown
25 White/Blue Grey
26 Red/Blue Blue
27 Red/Blue Orange
28 Red/Blue Green
29 Red/Blue Brown
30 Red/Blue Grey
31 Blue/Black Blue
32 Blue/Black Orange
33 Blue/Black Green
34 Blue/Black Brown
35 Blue/Black Grey
36 Yellow/Blue Blue
37 Yellow/Blue Orange
38 Yellow/Blue Green
39 Yellow/Blue Brown
40 Yellow/Blue Grey
41 White/Orange Blue
42 White/Orange Orange
43 White/Orange Green
44 White/Orange Brown
45 White/Orange Grey
46 Orange/Red Blue
47 Orange/Red Orange
48 Orange/Red Green
49 Orange/Red Brown
50 Orange/Red Grey
51 Orange/Black Blue
52 Orange/Black Orange
53 Orange/Black Green
54 Orange/Black Brown
55 Orange/Black Grey
56 Yellow/Orange Blue
57 Yellow/Orange Orange
58 Yellow/Orange Green
59 Yellow/Orange Brown
60 Yellow/Orange Grey

Wiring Colours for CW1128 & CW1326 External Telephone Cable
Pair No. 'A' wire 'B' wire
1 White Blue
2 White Orange
3 White Green
4 White Brown
5 White Grey
6 Red Blue
7 Red Orange
8 Red Green
9 Red Brown
10 Red Grey

Wiring Colours for  CW1406, CW1411 & CW1417
External Dropwire Cable
CW1406 CW1411 CW1417    
1-Pair No.10B 2-Pair No.12 4-Pair No.14 'A' wire 'B' wire
1st pair 1st pair 1st pair Orange White
n/u n/u 2nd pair Red Grey
n/u n/u 3rd pair Blue Brown
n/u 2nd pair 4th pair Green Black

 Colours for CW1109 Jumper Cable used on Main Distribution Frames (MDF) inside BT Telephone Exchanges

Application

'A' wire

'B' wire
TXE4 & misc. non PSTN BT circuits Blue Yellow
System X circuits Green Black/white
System Y (AXE10) Orange Turquoise
Private circuits Pink Grey
Featurenet & Redcare circuits Red Yellow
DACS & WB900 Circuits Green Yellow
P wire busying Green -

 Wiring Colours for CW1109 Jumper Cable used in Bodington Telecom Box Connections

Application

'A' wire

'B' wire
Trunk wiring Red  White
Extension wiring Blue Yellow
Superset wiring Green Orange
Private circuits    
Earth Green -

CW1109 Jumper wire is available in various colours, including, red/white, red/black, blue/yellow, blue/white, green/white, green/black and pink/grey. It is used for connecting MDF's and for Krone disconnection strips.

For further technical information on telephone cables, see the Belden web site

 

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