Monday, February 26, 2007

Serial Cables - Serial Data Communication

Serial Connectivity (

As technology has advanced and we've needed to pass more and more data more and more quickly between devices, serial communication has become more important. Serial communication transmits data in a precise series so that minimum skewing or modulation occurs. While it isn't as fast as parallel communication in short distances, it is superior, especially in long distances and when speed isn't exactly an issue, to older standards.

In order to make sure that all manufacturers that used serial communication could connect together, the EIA/TIA created the RS-232 standard. This way, serial keyboards, joysticks, scanners, and other equipment could be connected to terminals like computers. That same standard is followed today, but affects mainly the devices being connected, not the connection itself. Two devices with RS-232 compliant ports should be able to connect with any serial cables.

The most common connector type on a serial cable is the DB-9 connector. This D-Subminiature style connector has 9 pins in a "D" shaped footprint. L-com carries a wide variety of these types of cables, including economy D-Sub cables, deluxe, and premium (double shielded) style. These are all molded and factory terminated and tested.

Wednesday, February 21, 2007

Coaxial Crimp Tools

Coax Crimping Tools (

Coax cables are relatively easy to put together, if you have the right equipment and know what you're doing. That is because most coax connectors are "crimp style". That isn't to say all of them are, but twist-ons don't always get as great a connection, solder styles are sometimes sensitive to bending and flexing, and compression styles are just rare.

If you are going to be making a lot of coax cable assemblies, you'll need a coax crimping tool. These are fairly wrench-like in shape and design, but in the jaws of the devices there is a "hex" shaped hole. Different coax connectors require different sized hexes to properly crimp them.

When you are buying coax connectors, make sure to check with the manufacturer what the crimping dimensions are. At L-com, we usually put them on the engineering drawing, which you can freely download from our site. Once you know the crimping dimensions, make sure that you have or that you get a crimping tool with the correct sized hex die. Many crimping tools have the dies already permanently attached so you don't have to worry about losing extra pieces. But other crimp tools are more like frames for interchangeable dies, allowing you to use the same tool in multiple situations.

If you need help selecting a tool for your job, contact us at L-com and we will walk you through it!

Thursday, February 15, 2007

Category Rated Modular Couplers

Modular Couplers for Phone and Ethernet (

One of the great things about modular networks is that they're... well... modular! Networks in these cases are easily set up and customizable to whatever architecture you'd like to employ.

A key component of modular networks are the couplers. Most often these are designed to be panel mountable, so they can be mounted either in a wiring closet rack panel, or in a faceplate or wall plate at a workstation.

Because modular couplers have become so ubiquitous, a large variety of colors, shapes, and make-ups are now available. L-com carries a line of modular couplers called the ECF series that have a flange that can be screwed down to a panel. Apart from that, a popular style of panel-mount coupler is the keystone style. These are designed to snap-in to holes cut to the correct dimensions.

Make sure, when you source your coupler, that you get one that meets your applications. For instance, if you are going to be using shielded twisted pair cabling (STP), you should get shielded modular couplers as well. Also, a network will run at the speed of the lowest category rated component. So, if you have a Category 5e network set up, don't try to put a Category 3 coupler in it because that will slow the whole network. You can use a higher category rated coupler, such as a Cat 6 coupler, but don't go lower.

At L-com, you can get the panel dimensions from our couplers on the engineering drawings, download-able for free from the item level page of each coupler.

Wednesday, February 07, 2007 Web Site Update

Updates to (

I apologize that
I hadn't written a blog entry in so long, but we've been cooking up lots of events here at L-com. The web site is now updated with all sorts of enhancements. The first that you'll notice is the image on our home page is now a rotating gif and is clickable. Clicking on the item family that you see will bring you to a page where you can browse that kind of item.

In searches, you will notice that the page numbers are listed rather than just a "next" and "previous" button, as we had before. This will let you flip through our huge connectivity product listings more easily. We've also updated the search engine on our site to be a little more intuitive.

You may notice that on the left-hand side of our pages the navigation has changed slightly. We now list "Shop By Type" above "Shop By Category", and we've included a link to Overstock and Sale Items.

The biggest changes, though, are when you place an order online. We want the process of shopping online to be as convenient as calling or faxing orders to us.

First, when you add a cable, connector, adapter, or other connectivity product to your cart, you won't be sent to the cart page and have to back up if you want to add more items. Instead, you'll get a message that your cart has been updated and you'll stay where you are until you've finished shopping. You may see the cart icon at the top of the page blink red when there's something in it just to remind you that its there.

When you check out, if you are a new user, you won't need to enter your password up front. We'll let you go through the whole process first. You will have to put in a user name and password at the end, but we won't make you re-type all your information. We'll take it from your billing address. Speaking of the billing address, if you want to copy that to the shipping, you can easily do that now, no need to manually type it in.

Is that it? No, there's lots of other little enhancements all over the site. Check it out! Explore the whole line of products, check out the free technical information, and be sure to let us know if you have suggestions or ideas! We maintain our website for you, after all, to make shopping easier for you and more convenient.

Monday, January 29, 2007

L-com Connector Chart

What do you call this connector?(

Like any industry, the connectivity industry has its jargon and unique terms. Among the more frustrating is the complicated names of connector types. Do you need a BNC or an RCA? Do you have a DB15 or an HD15? What the heck is the difference between a MD6 and a PS/2?

Fortunately, one of L-com's more popular pages on its web site,, is the connector chart page. This is a free page that anyone can access to see pictures of connectors next to their names. Need a closeup? Click on any of the pictures and you can get a blown-up version to compare to your own product.

The connector chart is just one of the free educational benefits to L-com's web page, which includes tips, tutorials, video tips, educational newsletters, and white papers. On top of that, you can get CAD models, engineering drawings, and more details on most of our products for free as well! So, even if you're not ready to buy connectivity products, if you have an interest in them our site is worth a visit. Check it out here:

Monday, January 22, 2007

Industrial Rated Networking Equipment

IP67 and Harsh Environment Rated Active Networking Equipment (

The benefits of connectivity are everywhere, nowadays. This includes factories, controlled environments, and even the outdoors. But the equipment needed to set up and maintain a network is often sensitive to dust, water, temperatures, changes in voltage, etc. So in these situations, you need an industrial rated Ethernet device.

The most common Ethernet networking devices that need to be protected from the harsh environment are Ethernet routers and Ethernet switches. Hirschmann and GarrettCom are two manufacturers that provide excellent quality industrial rated products, though there are many on the market.

In addition to switches and routers, you may need media converters, cables, and peripheral devices like IP cameras. You may also want to consider getting a IP67 rated enclosure, or using sealing grommets to allow cables to go between harsh environments and office environments without letting the elements seep in.

If you have very specific requirements for your active device, let L-com know! We may be able to contact our many manufacturing partners and find a device that fits your needs.

Wednesday, January 17, 2007

Technical Support Help

L-com's Technical Support (

I've worked in L-com's Tech Support for a few years now and we've seen a lot of the same questions asked over and over. For that reason, we're creating a "Frequently Asked Questions" (FAQ) section of our web site! We're adding questions as they come to us, but please help us out by letting us know your favorite questions about connectivity, signal technology, or L-com itself.

We will keep putting questions up and, soon, modify our site search so you can easily search those questions for answers. That's not to say we don't want you to call us anymore! There's no way we can put down every single question someone might ask, and, truth be told, we really like working with our customers to help them find the answers to their questions.

Did you know we have dedicated tech support reps connected to a phone queue all day long? They answer questions quickly, and if they don't know the answer right off the bat, they'll research and get back to you, usually within a day. You can also email directly to tech support at, and get a response within 24 hours!

So, with our FAQ and Technical Resources online, and our live tech support resources offline, you can get all the answers you need to make an informed decision.

Tuesday, January 16, 2007

HDMI Cables - Emerging Video Cable Standard

HDMI Cable Assemblies and Components (

With a growing number of HDMI adopters, it's looking like HDMI may emerge as the reigning king of digital video connection types, at least in the consumer electronics side of things. But it joins a huge market of video standards, including HD15 SVGA connectors, DVI c
onnectors, S-Video (SVHS) connectors, RCA connectors for composite or component video, SCART connectors, and coax connectors like BNC or F type connectors for RF video. And the game isn't over yet, new video standards are still emerging so who knows what we will be using a year from now?

HDMI has a lot of advantages that make it preferable to other video types. It is digital, allowing the pixel-perfect video that is preferred over analog video by many a/v enthusiasts. It is small and easy to connect, and it can carry audio as well as video, a huge plus over most other video connector types. Early on, HDMI ran into the 5 meter length limitation of digital video, but improvements in cable technology have lead to longer versions of HDMI cables hitting the market.

Look for a host of new HDMI components to come out over the next year or so. HDMI cables will probably be joined by HDMI couplers, adapters, rack panels, and active equipment like HDMI extenders. As the standard gains in public acceptance, it will also make components that use the standard easier to roll out for smaller manufacturers.

Friday, January 05, 2007

Surface Mount Boxes and Wall Plates

How Do You Create Modular Ports for Your Users to Plug Into? (

Undoubtedly, one of the most important technological advances of our time is the modular network. Networked together, machines throughout an office, a building, a whole country, or all over the world can all communicate. In order to make a network user friendly, it's a good idea to provide easily accessible ports or jacks where your users' machines are.

Traditionally, there are two main ways of mounting modular jacks: in a wall or in a box mounted on a surface. By far, wall plates and face plates are the most popular way to go. With them, the jacks are flush with the wall, out of the way, but still easy to get to. But in some cases there are either no walls close by, or the walls cannot have anything running inside them. In those cases, surface mount boxes provide a perfect solution.

Boxes and face plates often come separate from the jack itself, allowing you to mix and match the correct jack with the correct mounting medium. Make sure you get a plate with the proper hole size already in it so you can easily mount the jack. The most common hole size is called Keystone, and though it is not standardized it is roughly the same from company to company.

Wednesday, January 03, 2007

DVI Video Standard

Digital Video Interface (DVI) - What is it?


DVI is one of the video standards for the emerging field of digital video. As you get newer televisions, HDTV boxes, video cards for PCs, and other video equipment, you may see this type of connector more and more.

The connector is shaped vaguely like a D-Sub connector, with screws on either side to hold it mounted. It has up to 24 pins in the middle, plus four pins possibly around a bar to one side. I say "up to 24 pins" and "possibly around a bar" because there are actually several types of DVI connectors possible.

Three DVI signal types

In instruction booklets that reference the DVI cables you need, you may see a letter after DVI, like this: "DVI-D". There are actually three different types of DVI: DVI-A, DVI-I, and DVI-D. The -A is for analog only, the -D is for digital only, and the -I has both analog and digital pins. How can you tell the difference? The easiest way is to look at the bar at one side of the connector. The four pins around it are for analog signals, so if you do not have those pins, the connector is a DVI-D: it only includes digital lines. If you do have pins around the bar, and most of the pins in the center (there may be a strip of pins missing in the middle. More on this in a second), you probably have a DVI-I connector. If you only have 12 of the middle pins, you probably have a DVI-A connector.

On a male connector, usually on a DVI cable, it is important to know which type it is because if you try to plug a connector into a female port that doesn't have enough holes for the pins, then some of the pins may bend, destroying the cable. On the other hand, female DVI-I connectors can accommodate both DVI-D and DVI-A connectors because they have holes for all of the pins. Most newer DVI equipment is coming with DVI-I connectors standard for that reason.

Single Link and Dual Link DVI

Single Link and Dual Link has to do with how many channels of transmission are available in a cable assembly. You can visually tell a single link male connector from a dual link by the centermost vertical strip of pins. If they are missing, then the cable is single link only. If they are there (meaning all 24 pins are present), then the cable is dual link.

Contrary to many beliefs, dual link isn't really "better", in that the picture quality is the same. Dual link is primarily for getting up to very high resolutions, usually too high for most TVs to get to. Dual link DVI can reach a resolution of 2048 x 1536 at 60 Hz Refresh Rate, sometimes called QXGA or Quad Extended Graphics Array. In most commercial cases, this isn't necessary.