[Rees Guitars]

Hello,
I need someone to tell me what wires correspond to what pin on a 10 pin connector. Websites I have looked at tell me different arrangements each time. Would the wire with the red dashes on it be pin #1?

Thanks,
Ed

[Al_The_Man]

If you are talking IDC ribbon connector then wire #1 is usually coloured red, the rest grey.
If mulit-coloured ribbon, the wire numbers/colours correspond to the Same as resistor colour code. 1 to 0 (10)
Al.

[ChipsNChips]

Again assuming we are talking about ribbon cable, yes the red or marked wire is ususlly pin #1. If the rainbow ribbon, then it does follow resistor color code and a brown wire on one side of the ribbon will be #1.

However, after pin #1 it is not that simple and it depends on the type of connector and in some cases on the whims of the design engineer. The two most popular connectors used with ribbon cable are the D-subminiatures (DB-9, D-15, DB-25, etc.) and the header connectors which have two rows of holes in a rectangular configuration. The header connectors usually have a 1/10 inch spacing for both the rows and the columns and are always female with pins on the PC board for the male component.

D subminiature connectors all have an odd number of pins in two rows. One row has one more pin than the other, thus a DB-9 will have a row of 4 and a row of 5 pins. They are numbered with the number 1 pin at one end of the longer row and the numbers proceed down that row to the end. Then they continue on the shorter row, in the same direction. Because the pins are offset in the two rows, the connections to the pins in the second row wind up inbetween the pins of the first row, thus on the ribbon cable the sequence is like this for the DB-9: 1, 6, 2, 7, 3, 8, 4, 9, 5. The DB-25 starts out like this: 1, 14, 2, 15, 3, 16, etc.

The header connectors are another story. They also have two rows of pins and the number 1 pin is at the end of one row. But the two rows are the same length so they always have an even number of pins. Again, the pins of the second row have their connections brought out inbetween the pins of the first row. But, there is no standard numbering scheme for the pins. Some designers number in the same manner as the DBs and others will assign the pin numbers to correspond to the positions in the ribbon cable. Thus a 10 pin header connector could have two possible pin orders in the ribbon cable. 1) 1, 2, 3, 4, 5, etc. and 2) 1, 9, 2, 10, 3, 11, etc. The only way to know is to look at the schematic or perhaps it may be etched in the foil pattern on the board. The connectors do not have any numbers on them.

All of the above assumes that the manufacturer even follows the unwritten, ununique conventions.