Cabling

The following technical wiring specifications have been compiled and tested by Syrex Intranets. This information is primarily usefull to support engineers, and IT professionals, that are wanting to construct or check certain network or cable configurations.

* 10Base-T wiring
10Base-T wiring CAT 3 wire pairing

The pinouts are for RJ45 8pin sockets. The terminology T and R comes from the old telecom days of 'Tip' and 'Ring' of jack plugs and corrosponds to the +ve and -ve on the twisted pair of cables and not Transmit and Receive of ethernet data!

colour stripe = Tip = +ve ; solid colour = Ring = -ve

Old CAT3 10Base-T only needs two pairs of would often be shown wired using pairs #1 and #2. It is however alternatively also shown to be wired using just pairs #2 and #3 as a subset of the more modern EIA568B (again all electrically compatible - just pair number and colour codes changed).

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* UTP Network wiring (up to 10Gbps)
100Base-TX wiring CAT 5 wire pairing

The pinouts are for RJ45 8pin sockets. The terminology T and R comes from the old telecom days of 'Tip' and 'Ring' of jack plugs and corrosponds to the +ve and -ve on the twisted pair of cables and not Transmit and Receive of ethernet data!

colour stripe = Tip = +ve ; solid colour = Ring = -ve

The CAT5 sockets (ModTap) supplied by RS are generally colour coded to the EIA568B standard (which was the old AT&T 258A standard).

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* UTP Crossover wiring (up to 10Gbps)
10Base-T and 100Base-TX crossover wiring 10Base-T and 100Base-TX crossover wiring CAT 5 wire pairing

The pinouts are for RJ45 8pin sockets. The terminology T and R comes from the old telecom days of 'Tip' and 'Ring' of jack plugs and corrosponds to the +ve and -ve on the twisted pair of cables and not Transmit and Receive of ethernet data!

colour stripe = Tip = +ve ; solid colour = Ring = -ve

The CAT5 sockets (ModTap) supplied by RS are generally colour coded to the EIA568B standard (which was the old AT&T 258A standard). In crossover cabling T1 connects to R4, T2 to R3, T3 to R2 and T4 to R1.

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* ISDN wiring
ISDN wiring CAT 5 wire pairing

The pinouts are for RJ45 8pin sockets. The terminology T and R comes from the old telecom days of 'Tip' and 'Ring' of jack plugs and corrosponds to the +ve and -ve on the twisted pair of cables and not Transmit and Receive of ethernet data!

colour stripe = Tip = +ve ; solid colour = Ring = -ve

The CAT5 sockets (ModTap) supplied by RS are generally colour coded to the EIA568B standard (which was the old AT&T 258A standard). ISDN is generally wired to the EIA568A (100Base-TX) standard. This is electrically compatible to EIA568B but the pair and color codes of 2 and 3 are swapped around.

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* USOC 4, 6 & 8 (Token ring) wiring
USOC 4, 6 & 8 (Token ring) wiring USOC 4, 6 & 8 wire pairing

The pinouts are for RJ45 8pin sockets. The terminology T and R comes from the old telecom days of 'Tip' and 'Ring' of jack plugs and corrosponds to the +ve and -ve on the twisted pair of cables and not Transmit and Receive of ethernet data!

colour stripe = Tip = +ve ; solid colour = Ring = -ve

USOC 4, 6 & 8 or more commonly known as Token ring wiring

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* Null Modem wiring
One connector is assembled from each side of the hyphens. The frame ground on the 25 pin plug is optional and should only be connected on one side of the cable.

If you need DCD (Data Carrier Detect) on your cable (BBS programs, Unix Getty and so on) then see below. The connections for DCD should be made on the same end of the cable.
  • On a 25 pin plug connect pin 6 and 8.
  • On a 9 pin plug connect pin 1 and 6.
Pin Connections:

  25 Pin 9 Pin   9 Pin 25 Pin  
FG (Frame Ground) 1   X   1 FG (Frame Ground)
TD (Transmit Data) 2 3 - 2 3 RD (Receive Data)
RD (Receive Data) 3 2 - 3 2 TD (Transmit Data)
RTS (Request To Send) 4 7 - 8 5 CTS (Clear To Send)
CTS (Clear To Send) 5 8 - 7 4 RTS (Request To Send)
SG (Signal Ground) 7 5 - 5 7 SG (Signal Ground)
DSR (Data Set Ready) 6&8 6&1 - 4 20 DTR (Data Terminal Ready)
DTR (Data Terminal Ready) 20 4 - 6&1 6&8 DSR (Data Set Ready)

Where to find Pin 1:
  Female Male
25 pin (DB25) 25 pin Female (DB25) 25 pin Male (DB25)
9 pin (DB9) 9 pin Female (DB9) 9 pin Male (DB9)

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* Laplink cable wiring
One connector is assembled from each side of the hyphens. This is the wiring diagram for the cable necessary to link two machines together by their parallel ports for a LapLink connection. You can also use such a cable in combination with the PLIP packet driver to simulate an Ethernet running on two machines. FastLynx is another program that enables communication between PCs via a parallel cable.
  • Cable pin connections used on both types of cables.
  • Laplink/Interlink cable pin connections.
  • FastLynx 2.0 cable pin connections.
Pin Connections:

  25 Pin   25 Pin  
Strobe 1 - 1/7 Strobe/Data bit 5
Data bit 0 2 - 15 Error
Data bit 1 3 - 13 Select
Data bit 2 4 - 12 Paper out
Data bit 3 5 - 10 Ackn.
Data bit 4 6 - 11 Busy
Data bit 5 7 - 1 Strobe
Data bit 6 8 - 14 Autofeed
Data bit 7 9 - 16 Initialize
Ackn. 10 - 5 Data bit 3
Busy 11 - 6 Data bit 4
Paper out 12 - 4 Data bit 2
Select 13 - 3 Data bit 1
Autofeed 14 - 14/8 Autofeed/Data bit 6
Error 15 - 2 Data bit 0
Initialize 16 - 16/9 Initialize/Data bit 7
Select Input 17 - 17 Select Input
Ground 18 - 18 Ground
Ground 25  - 25  Ground

Where to find Pin 1:
  Female Male
25 pin (DB25) 25 pin Female (DB25) 25 pin Male (DB25)

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* 3Com Palm III Cradle to Modem Cable
One connector is assembled from each side of the hyphens.

Pin Connections:

  9 Pin Male   25 Pin Male  
DSR (Data Set Ready) 6 - 20 DTR (Data Terminal Ready)
TD (Transmit Data) 3 - 3 RD (Receive Data)
CTS (Clear To Send) 8 - 4 RTS (Request To Send)
RD (Receive Data) 2 - 2 TD (Transmit Data)
RTS (Request To Send) 7 - 5 CTS (Clear To Send)
SG (Signal Ground) 5 - 7 SG (Signal Ground)

Where to find Pin 1:
  Female Male
25 pin (DB25) 25 pin Female (DB25) 25 pin Male (DB25)
9 pin (DB9) 9 pin Female (DB9) 9 pin Male (DB9)

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* PS/2 Mouse & Keyboard connections
Pin Connections:

Pin Signal
1 Data
2 Not used
3 Ground
4 +5V DC
5 Clock
6 Not used

Where to find Pin 1:
  Female Male
6 pin (PS/2) PS/2 Female PS/2 Male

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