Home | Contact Us | Search | Useful Links

D-sub 9 Connector

The DE-9 D-sub 9-pin connector is often mistakenly referred to as the "DB-9" connector. The "E" refers to the shell size. A "DB-25" connector has a "B" size shell, but the common nine-pin connector is smaller and has an "E" size shell.

This connector (regardless what you call it) is used for a variety of purposes. Two common applications are RS-232/EIA-232 (serial) connections (including UPS cables), and a variety of video interfaces on the IBM PC.

Here's a good set of figures for D-sub 9 male and female connectors, as viewed from the pin side (not the solder side).

DB-9 Male

D-sub 9 Male

DB-9 Female

D-sub 9 Female

Pins commonly used for RS-232/EIA-232 (serial):

DB-25	D-sub-9	Signal Direction	Signal Name
1		x	Protective Ground
2	3	DTE-to-DCE	Transmitted Data
3	2	DCE-to-DTE	Received Data
4	7	DTE-to-DCE	Request To Send
5	8	DCE-to-DTE	Clear To Send
6	6	DCE-to-DTE	Data Set Ready
7	5	x	Signal Ground
8	1	DCE-to-DTE	Received Line Signal Detector (Carrier Detect)
20	4	DTE-to-DCE	Data Terminal Ready
22	9	DCE-to-DTE	Ring Indicator

Click here to see the pin out of DB-25 connectors.

Common Null-Modem Connection

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

Click here to see the pin out of DB-25 connectors.

D-sub 9 pins commonly used for the IBM-PC CGA (color) video:

Pin	Description
1	Signal ground
2	Signal ground
3	Red video
4	Green video
5	Blue video
6	Signal intensity
7	Unused
8	Horizontal sync
9	Vertical sync

Click here to see the pin out of HD-D-sub15 connectors (used for VGA).

D-sub 9 pins commonly used for the IBM-PC EGA (color) video:

Pin	Description
1	Signal ground
2	Secondary red
3	Red video
4	Green video
5	Blue video
6	Secondary green / signal intensity
7	Secondary blue / Monochrome
8	Secondary blue / horizontal sync
9	Vertical sync

Click here to see the pin out of HD-DB-15 connectors (used for VGA).

D-sub 9 pins commonly used for the IBM-PC MGA/HGA (monochrome) video:

Pin	Description
1	Signal ground
2	Signal ground
3	Not used
4	Not used
5	Not used
6	Signal intensity
7	Video signal
8	Horizontal sync
9	Vertical sync

D-sub 9 pins sometimes used for VGA (color) video:

Pin	Description
1	Red Video
2	Green Video
3	Blue Video
4	Horizontal Sync
5	Vertical Sync
6	Red Ground
7	Green Ground
8	Blue Ground
9	Sync Ground

Click here to see the pin out of HD-D-sub 15 connectors (used for VGA).

All trademarks and copyrights on the CD's are owned by their respective companies.

__________________