9 Things You Need to Know about D-Subminiature Connectors

November 2, 2017 at 8:00 AM

 

Serial communication once reigned supreme. It used to be one of the most popular ways to connect peripherals such as printers, scanners, mice and joysticks to PCs. The most common connector type for serial communication was the D-subminiature connector, also called D-sub. Though they have been replaced in some applications, D-sub connectors are still relevant and used in many ways today.

 

Here are 9 things you need to know about D-subminiature connectors:

 

1.  D-subminiature connectors were once among the smallest connectors used on computer systems. They are named for their D-shaped metal connector shell. The metal shell surrounds two or more parallel rows of pins or sockets that carry the data in series.

 

2.  There are five different connector shell sizes. Each shell size can have two different configurations of pins. The standard shell size has two rows of pins and the high-density versions have three rows of pins.

 

3. With individual pins to carry serial data, D-sub connectors are very easy to customize. The DB9 is one of the standard configurations and has the smallest shell size, with 9 pins in the shell and measuring 1.3cm tall and 3.1cm wide. The largest, high-density configuration is HD78, with 78 pins it measures 1.5cm tall and 6.7cm wide. To see all shell sizes and D-sub configurations, click here.

 

4.  Cables using D-sub connectors can cover much longer lengths than other cables. RS-232, the current common standard for serial data, doesn’t have a defined length limit and RS-422 can be used over hundreds of meters with special equipment. On the other hand, USB has a length limit of five meters.

 

5.  Serial communication tends to be slow, especially over long lengths. Breaks in communication can cause software on a PC to freeze unexpectedly.

 

6.  D-Sub connectors are large, especially when compared to newer connector designs. This makes them difficult to connect and disconnect in tight spaces. Though right-angle adapters help in small spaces by allowing a right-angle bend without damaging the connector.

 

7.  Because the pins are exposed on these connectors, they can be easily bent or broken off in the shell. The best way to avoid broken pins is to use a D-sub plug or jack cover to protect the pins from being damaged when not mated. Also, gender changers and socket savers can help reduce stress from repeated mating cycles.

 

8.  D-subminiature connectors can be mated without thumbscrews but a friction-fit it does not always hold. Using thumbscrews makes for a more secure connection, but it does take longer to plug and unplug the connector.

 

9.  There are still many devices with DB9 ports and plenty of conversion options for legacy D-sub connectorized products. Converters to and from RS232/422/485 to USB, Ethernet and other technologies allow you to use your old serial device with many of today’s computers.

 

Video Blog- L-com's Toughest Cable Field Test

November 3, 2016 at 8:00 AM

 

Have you ever wanted to test your cables and really push them to the limit? If so, we have a video you MUST watch. We wanted to see just how much abuse our metal armored cables could endure, so we put them through our toughest test ever.

 

Our series of metal armored cables are capable of withstanding the harshest environments and are specifically designed for outdoor, industrial and military applications. Rugged metal armor protects the cable from damage and provides up to 1,500 pounds per square inch (PSI) of crush resistance. The metal jacket also secures the cable from dust, oil, moisture and UV damage. These cables can be used in a variety of industrial applications including factory automation, manufacturing and chemical or petroleum processing networks.

 

Our metal armored cables are currently available off-the-shelf in USB, DVI, HDMI, Ethernet (RJ45) and D-Subminiature styles. Plastic armored cable assemblies with up to 800 PSI of crush resistance are also available. In addition to our extensive off-the-shelf armored cable offering, we can also design and manufacture armored cables to your specifications.

 

Now, check out the video to watch our field test and see just how tough our armored cables are.

 

 

For more videos, tips and tutorials, click here.

 

DB9 D-Subminiature Connectors : Advantages and Disadvantages

June 19, 2013 at 10:00 AM

9-pin D-Sub connectors (DB9 or DE-9)

 

DB9 Connector on Cable

For many years, serial communication was one of the chief methods of connecting peripherals (such as joysticks, printers, and scanners) to PCs. The most common connector type for serial communication was the 9-pin D-Subminiature connector, or sometimes called a DB9 or a DE-9.

 

Nine pins were plenty to carry the data in series, and though there were many drawbacks to DB9 connectors which eventually lead to them becoming legacy in favor of standards like USB, there are still many devices with DB9 ports or cables on them today.

 

 

What are the disadvantages?

 

The connectors themselves are large, making them difficult to connect and disconnect in tight spaces. Also, the pins are exposed in the shell, so they can be easily bent or broken off. Though the connector can be mated without using the thumbscrew hardware, it does not tend to hold as well using just friction-fitting. If you do use the thumbscrews, the connector takes much longer to plug in and unplug.

 

Finally, serial communication tends to be slow, especially over longer lengths, and unexpected breaks in communication could cause software on the PC to freeze. All of these problems led to other standards becoming more popular for the same applications.

 

However, this does not mean that the DB9 connector is a lost cause. There are actually solutions available for many of the problems mentioned above. For instance, right angle adapters solve the tight-space problem by allowing a tight angle without damaging the connector. Widely available D-Subminiature plug and jack covers can protect pins from damage when not mated, and adapters like gender changers and socket savers can reduce the stress caused by repeated mating cycles.

 

 

On the other hand...

 

ES4-232 4-Port Ethernet to DB9 Adapter and Device Server

DB9 connectors have advantages too. In general they are far easier to customize, with at least 9 individual pins to carry serial data. Though the speed is slower than other standards, the length of the cable can be much longer. USB, for instance, has a five-meter length limit, but RS-232 (the most common standard for serial data) has no defined length limit, and RS-422 has been used at lengths hundreds of meters long with special equipment.

 

Also- Don't worry if you have an old device that only has DB9 connectors on it. Even with D-Subminiature being mostly legacy, there are plenty of options for conversion. Converters to and from USB, Ethernet, and other standards are common and can allow you to use your device on any computer today.

 

Examples of Applications for Serial Converters

If you're looking to find DB9 Connectors: L-com carries products ranging from economical serial cables with many off-the-shelf lengths to high-quality premium cables for demanding applications. Also check out L-com's D-Subminiature adapters for innovative solutions to common problems, and L-com's bulk cable, connectors, adapter kits and tools for do-it-yourself components.
 
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