The DB9 connector is a type of D-sub (D-subminiature) connector family, named because it has 9 pins (or holes), and is widely used in serial communication, industrial control, instrumentation and other fields. Although the name "DB9" is often used to refer to D-sub connectors with 9 pins, from a strict standard, its complete classification and types are still relatively rich. The following is a complete description of the types of DB9 connectors under various classification methods:
I. Classification by gender:
DB9 connectors are divided into two genders:
1. DB9 male (Male):
- Features: with 9 pins
- Common code: DB9M or DE-9M
- Use: often used as a signal output terminal, such as PC serial port output
2. DB9 female (Female):
- Features: with 9 holes
- Common code: DB9F or DE-9F
- Use: often used as a signal input terminal, such as a serial device interface
II. Classification by installation method:
1. Cable type (Cable Mount)
- Straight cable end connector
- Elbow cable connector (90 degrees)
- Weldable wire type or with crimping connector/screw type
2. Panel mount type (Panel Mount)
- With mounting ears (flange)
- Installed on the equipment panel, usually used for industrial equipment, instruments and meters
3. PCB board end type (PCB Mount)
- Straight through hole
- 90 degree bend type (Right Angle)
- Used for welding on PCB circuit boards, widely used in control boards, IO boards, etc.
III. Further subdivided by installation method (process):
- Through-Hole (THT)
- Surface Mount (SMT)
- Crimp
- Solder Cup
IV. Classification by interface definition/protocol:
1. RS-232 interface uses DB9
- The most common serial communication use, the typical 9-pin definition is as follows (such as PC serial port):
- Pin 2: RXD (receive)
- Pin 3: TXD (transmit)
- Pin 5: GND (ground)
2. RS-485/RS-422 interface uses DB9
- Commonly used in industrial equipment, DB9 connectors may also be used, and the pin definition varies from manufacturer to manufacturer.
3. DB9 for CAN bus interface
- General standard definition such as 9-pin definition specification used by CANopen
4. DB9 for Profibus interface
- Common in Siemens PLC, inverter communication, etc.
5. Custom interface
- Some manufacturers or engineering projects will use DB9 for completely different signal transmission, and the pin function is customized
V. Classification by shielding method:
- Unshielded
- Shielded Metal Shell
- Improve anti-electromagnetic interference (EMI)
- With built-in grounding spring type (EMI Ground Spring)
VI. Classification by termination method:
- Solder Type
- Crimp Type
- IDC Type (Insulation Displacement Wiring)
- Screw Terminal
- Suitable for field wiring, low tool requirements
VII. Classification by shell material:
- Plastic shell
- All-metal shell
- Metal + plastic combination shell
VIII. According to whether it comes with accessories:
- With fixing screws (Thumbscrews / Jack Screws)
- Without fixing screws
- With waterproof cover or dust cover
- With zipper cover / injection molded cover
IX. Classification by protection level (IP level):
- Ordinary type (no special protection)
- Waterproof type (such as IP65, IP67 level)
- Industrial field communication, automotive electronics applications
X. Compatibility by brand/standard:
- Standard DB9 (DE-9) connector
- High-density type (High-Density D-sub)
Similar shape but higher pin density
- Mini D-sub or Micro D-sub
Smaller size but similar appearance, such as a smaller version of HD15
