Hartwick Communications Consulting

Cable Pinouts

This page was created years ago and persists just because like most IT people we don't like to delete things. If anyone finds an error please feel free to contact us to point it out, however, it is unlikely that there will be any further additions to this page.

In this section you will find the pinout for various commonly used connectors in communications equipment. As I find more pinouts I will add them to my list. You can use the Index to jump the the connector or cable you are interested in.

Index


DB-25

The directions in this table are for DTE equipment. The diagram below is for a male DB-25 connector. As you move from right to left and top to bottom the pin numbers increase. The 0 in the first row is actually pin 10 and the on to it's right is 11 etc. The 0 in the bottom row is 20.

 ___________________________
( 1 2 3 4 5 6 7 8 9 0 1 2 3 )
 \ 4 5 6 7 8 9 0 1 2 3 4 5 /
  `-----------------------'
      
Pin Signal Direction
2 TxD out
3 RxD in
4 RTS out
5 CTS in
6 DSR in
7 GND n/a
8 DCD in
20 DTR out

Return to the Index.

DB-9

The directions in this table are for DTE equipment. The diagram below is for a male AT style DB-9 connector.

 ___________
( 1 2 3 4 5 )
 \ 6 7 8 9 /
  `-------'
      
Pin Signal Direction
1 DCD in
2 RxD in
3 TxD out
4 DTR out
5 GND n/a
6 DSR in
7 RTS out
8 CTS in
9 RI in

Return to the Index.

10Base-T

As far as I know this is the proper order for Cat 5 cables. I do know that the twists are maintained and noise should not be a problem.

Pin Colour Signal
1 White Orange ?
2 Orange ?
3 White Green ?
4 Blue N/A
5 White Blue N/A
6 Green ?
7 White Brown N/A
8 Brown N/A

Return to the Index.

10Base-T Crossover

This allows you to connect two computers using 10Base-T without using a hub. This will NOT work when connecting with a hub.

Pin Colour Pin
1 White Orange 3
2 Orange 6
3 White Green 1
4 Blue N/C
5 White Blue N/C
6 Green 2
7 White Brown N/C
8 Brown N/C

Return to the Index.

T1 Crossover

This can be used to connect two CSU/DSU's as long as one is set to provide clocking.

Pin Signal Pin
1 Receive Ring 4
2 Receive Tip 5
3 N/C N/C
4 Transmit Ring 1
5 Transmit Tip 2
6 N/C N/C
7 N/C N/C
8 N/C N/C

Return to the Index.

T1 Hard Loop

This is a very handy tool for testing T1 circuits. It places a hard loopback in a T1 circuit. By using a hardloop you can test various parts of a circuit by eliminating pieces from the equation.

This is made in 1 RJ-45 plug with 2 pieces of wire of 10-20 cm.

Pin Signal
1 Loop to 4
2 Loop to 5
3 No connection
4 Loop to 1
5 Loop to 2
6 No connection
7 No connection
8 No connection

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