All You Wanted to Know About DB9 Connectors

If you deal in cable and connectors, you must have come across the term DB9 Connector. This connector is named like that because of its trapezoidal shape that looks like letter "D". It has been designed in such a way that it can work with EIA/TIA 232 serial interface standard and used for Serial Asynchronous Data Transmission. You will find DB9 Connectors used with computer, audio/video, and data applications. DB9 ports were quite popular during the initial years; but with the introduction of usb, firewire etc its popularity declined.

The RS 232 is the recommended standard for enabling serial data transfer between DCE (Data Circuit-terminating Equipment) and DTE (Data Terminal Equipment). When you buy these connectors, you can recognize them by the letters A to E that denote the shell size and also by the number of pins. M or F indicates whether it is a male or a female connector. Let us know more about these connectors, their types, electrical specifications and applications:

DB9 Connector –Sizes and Types

DB stands for D sub or D subminiature. However, its real name is DE-9. There are times when DE-9 D-sub 9-pin connector is wrongly referred to as "DB-9 connector". Here, "E" refers to the shell size. Every shell size of DB9 connector corresponds to a particular number of sockets or pins. For example, A with 15, B with 25, E with 9 and so on… DB9 indicates 9 position shell and 9 indicates contact terminals. They were used a lot in PC. Db-xx on the other hand is used for all types of serial connectors.

Electrical specifications of DB9 Connectors

1. Rating: 3 Amps max
2. Contact resistance: 20 mOhms max
3. Operation voltage: 250VAC max
4. Insulation resistance: 3000 MOhms min at 1000 VDC between
5. Dielectric withstanding voltage: 1000 VAC min rms (sea level)

Application of DB9 connectors

DB9 connectors are used for the following purposes:

• To connect peripheral devices in the outdated pcs
• With keyboard, mouse and joysticks
• In microprocessors evaluation board, circuit boards etc while programming
• Stepper and servo motor interface
• Modem and network

There are several firms through which you can buy DB9 Serial Cables and connectors online including SF Cable. You can get in touch with their experts and seek their advice before deciding on the type of cable you want. Once you get insights about the kind of cable you need, you can order it online. Make sure you are clear with the specifications and usage before you order for these cables and connectors.

Jennifer Truong is the owner of SF Cable, a california based online retailer of all kind of Computers, electronics, electrical accessories, networking accessories, cables, wires. Jennifer has extensive experience in the Electronics industry and blog.