In PCs, a sub-D connector (COM, Game / Midi or LPT) is often connected to a crimp or IDC (Insulation Displacement Connector) by means of a ribbon cable. IDCs have two rows of pins. One is even, the other odd numbered;
+-----+ +-----+
1 | * * | 2 2 | o o |< 1
3 | * * | 4 4 | o o | 3
5 * * | 6 6 | o o | 5
7 | * * | 8 8 | o o | 7
9 | * * | 10 10 | o o | 9
+-----+ +-----+
Male (motherboard) Female (cable)
Pin 1 on the connector is marked with a triangle. The corresponding wire is red.
There are two ways of connecting these to a DE-9, DA-15 or DB-25 connector;
AKA straight-through or '1:1'
DE-9 IDC-10 Signal 1 1 DCD 2 2 RXD 3 3 TXD 4 4 DTR 5 5 GND 6 6 DSR 7 7 RTS 8 8 CTS 9 9 RI
Pin 10 on the IDC is not used.
DE-9 Male
1 2 3 4 5
-----------------
\ * * * * * /
\ * * * * /
-------
6 7 8 9
1 DCD 6 DSR
2 RXD 7 RTS
3 TXD 8 CTS
4 DTR 9 RI
5 GND
IDC
DCD 1 * * 2 RXD TXD 3 * * 4 DTR GND 5 * * 6 DSR RTS 7 * * 8 CTS RI 9 * * 10 NC (Not Connected) or Key
This system is used by many Asus motherbords.
AKA crossed wiring or twisted.
DE-9 IDC-10 Signal 1 1 DCD 2 3 RTD 3 5 TXD 4 7 DTR 5 9 GND 6 2 DSR 7 4 RTS 8 6 CTS 9 8 RI
This system was used on the old ISA multi-IO cards.
It's also compatible with many ASUS motherboards.
DA-15 Female
8 7 6 5 4 3 2 1
-----------------------
\ o o o o o o o o /
\ o o o o o o o /
-------------
1 1 1 1 1 1
5 4 3 2 1 0 9
1 + 5 V (common for 1st set of pots) 2 Button 1 3 X Axis 1 (0-100 kOhm) 4 GND (ground for button 1) 5 GND 6 Y Axis 1 (0-100 kOhm) 7 Button 2 8 + 5 V 9 + 5 V (common for 2nd set of pots) 10 Button 4 11 X Axis 2 (0-100 kOhm) 12 Midi TX 13 Y Axis 2 (0-100 kOhm) 14 Button 3 15 Midi RX
IDC-16
+5V 1 * * 2 +5V J1B1 3 * * 4 J2B1 J1CX 5 * * 6 J2CX GND 7 * * 8 Midi Out GND 9 * * 10 J2CY J1CY 11 * * 12 J2B2 J1B2 13 * * 14 Midi in +5V 15 * * 16 NC (Not Connected) or Key
Pin 16 is not used.
On PCB's you will often find a different way to number 16 pin connectors;
Or; 1 * * 9 1 * * 9 2 * * 10 2 * * 10 3 * * 11 3 * * 11 4 * * 12 4 * * 12 5 * * 13 5 * * 13 6 * * 14 6 * * 14 7 * * 15 7 * * 15 8 * * 16 / NC 8 * 16 / Key
This corresponds to the DA-15 numbering.
Some Midi keyboards have a DA-15 connector. They get their power from the game port.
Some ASUS motherboards use this system.
DB-25 IDC26 1 1 2 3 3 5 4 7 5 9 6 11 7 13 8 15 9 17 10 19 11 21 12 23 13 25 14 2 15 4 16 6 17 8 18 10 19 12 20 14 21 16 22 18 23 20 24 22 25 24
Pin 26 on the IDC is not used.
DB-25 Female
1 1 1 1
3 2 1 0 9 8 7 6 5 4 3 2 1
---------------------------------
\ o o o o o o o o o o o o o /
\ o o o o o o o o o o o o /
-----------------------
2 2 2 2 2 2 1 1 1 1 1 1
5 4 3 2 1 0 9 8 7 6 5 4
1 -STROBE 14 -AUTOFEED
2 D0 15 -ERROR
3 D1 16 -INIT PRINTER
4 D2 17 -SELECT INPUT
5 D3 18 GND
6 D4 19 GND
7 D5 20 GND
8 D6 21 GND
9 D7 22 GND
10 -ACK 23 GND
11 BUSY 24 GND
12 P. END 25 GND
13 SELECT
IDC
-STB 1 * * 2 -AFD D0 3 * * 4 -ERROR D1 5 * * 6 -PINIT D2 7 * * 8 -SLIN D3 9 * * 10 GND D4 11 * * 12 GND D5 13 * * 14 GND D6 15 * * 16 GND D7 17 * * 18 GND -ACK 19 * * 20 GND BUSY 21 * * 22 GND PE 23 * * 24 GND SLCT 25 * * 26 NC (Not Connected) or Key
RXD--------\ /--------RXD
X
TXD--------/ \--------TXD
RTS--------\ /--------RTS
X
CTS--------/ \--------CTS
DTR--------\ /--------DTR
X
DSR--*-----/ \-----*--DSR
| |
DCD--+ +--DCD
GND---------------------GND
The shield of the cable should be connected (soldered) to the connector shell at both ends of the cable.
5 4 3 2 1
-----------------
\ o o o o o /
\ o o o o /
-------
9 8 7 6
DE-9 Female
2 --------\ /-------- 2
X
3 --------/ \-------- 3
7 --------\ /-------- 7
X
8 --------/ \-------- 8
4 --------\ /-------- 4
X
6 --*-----/ \-----*-- 6
| |
1 --+ +-- 1
5 --------------------- 5
1 1 1 1
3 2 1 0 9 8 7 6 5 4 3 2 1
---------------------------------
\ o o o o o o o o o o o o o /
\ o o o o o o o o o o o o /
-----------------------
2 2 2 2 2 2 1 1 1 1 1 1
5 4 3 2 1 0 9 8 7 6 5 4
DB-25 Female
3 --------\ /-------- 3
X
2 --------/ \-------- 2
4 --------\ /-------- 4
X
5 --------/ \-------- 5
20 --------\ /-------- 20
X
6 --*-----/ \-----*-- 6
| |
8 --+ +-- 8
7 --------------------- 7
Do not use pin 1; The shield should be connected to the connector shell.
25 pins 9 pins
3 --------\ /-------- 2
X
2 --------/ \-------- 3
4 --------\ /-------- 7
X
5 --------/ \-------- 8
20 --------\ /-------- 4
X
6 --*-----/ \-----*-- 6
| |
8 --+ +-- 1
7 --------------------- 5
This cable can also be used for interlink and plip
D0----------------------ERROR D1----------------------SELECT D2----------------------PE D3----------------------ACK D4----------------------BUSY ACK---------------------D3 BUSY--------------------D4 PE----------------------D2 SELECT------------------D1 ERROR-------------------D0 GND---------------------GND
1 1 1 1
1 2 3 4 5 6 7 8 9 0 1 2 3
---------------------------------
\ * * * * * * * * * * * * * /
\ * * * * * * * * * * * * /
-----------------------
1 1 1 1 1 1 2 2 2 2 2 2
4 5 6 7 8 9 0 1 2 3 4 5
DB-25 Male
2 --------------------- 15 3 --------------------- 13 4 --------------------- 12 5 --------------------- 10 6 --------------------- 11 10 --------------------- 5 11 --------------------- 6 12 --------------------- 4 13 --------------------- 3 15 --------------------- 2 18 ... 25 -------------- 18 ... 25
+ TXD ----\ /---- + TXD
\ /
- TXD ----\ X /---- - TXD
X X
+ RXD ----/ X \---- + RXD
/ \
- RXD ----/ \---- - RXD
+---+
+--+ +--+
+---+ +---+
| |
| | | | | | | | | |
| | | | | | | | | |
+-^-^-^-^-^-^-^-^-+
1 2 3 4 5 6 7 8
White / Orange 1 ----\ /---- 1 White / Green
\ /
Orange 2 ----\ X /---- 2 Green
X X
White / Green 3 ----/ X \---- 3 White / Orange
/ \
Green 6 ----/ \---- 6 Orange
I wonder to which extend these standards are in fact compatible.
1 Scr A 2 3 4 --- P 5 --- Y 6 --- R 7 --- C 8 --- V 9 --- D 10 --- L 11 --- E 12 --- H 13 --- F 14 --- N 15 16 17 --- U 18 --- NN 19 GND B 20 GND 21 22 --- S 23 --- AA 24 --- T 25 26 --- X 27 28 29 30 31 32 33 34 35 --- W 36 37 GND
The pins marked `GND' are connected to each other.
The pin marked `Scr' is connected to the shield.