7 Deadly Counterfeit Cable Sins for You to Avoid

January 30, 2014 at 10:00 AM

 

 

What scares you more than a faulty, over-rated, counterfeit cable? If you’re like us and work with cables on a daily basis, then you know the answer: nothing.  

 

Shockingly, unscrupulous sellers have found many ways to cut costs on cables, drawing customers in for the low price. But what they don’t tell you is that it comes at a price- sacrificing safety, performance, and network stability.

 

So how do you identify them? Counterfeit cables are bulk cables or cable assemblies sold under false pretenses to undercut legitimate manufacturers.  Usually this means the cable specification does not match the actual product construction. Or it could be that the seller falsely implies that a cable meets a particular performance standard or flammability rating such as Category 5E or CMP/Plenum.  If you get a low bid for your next cable quote, check these factors to make sure you are getting what you are paying for:

 
 
1. Substituting steel or aluminum for pure copper: copper-clad-steel (CCS) or copper-clad-aluminum (CCA) are classic methods of saving on costly copper needed to make cables. Over the length of the cable, however, the signal integrity will drop below the noise and cross-talk levels. There's a good reason the EIA/TIA has not approved CCS or CCA cable for use in high-speed networks…

2. Deceiving Connector construction: This is a two-part deception. For "RJ-45" (8p x 8c) connectors, rejected molded plastic bodies can be re-ground back to pellets, added to new plastic, and then made in new bodies, which can lower the combustion rating for the overall connector. A good tip: check the connector body for foggy or yellowing plastic. Aside from the body, the metal contacts are first coated with nickel then with gold to ensure a good connection. Manufacturers have been skipping the nickel and skimping on the gold, sometimes called gold flash or selective plating. Contacts made this way will eventually corrode and fail to connect when mated.

3. Cable Jacket Material: For those applications that require CMP or CMR flammability rating, the requirement is critical. If it is specified that the cable meets CMP or CMR ratings (per the NEC code) and you get an unusually low bid, ask for proof of the jacket material. A legitimate business will offer a signed Certificate of Conformance (CoC) for the product they sell.

4. Selective Electrical Performance Testing: Some manufacturers will claim their cable or cable assemblies were "Fluke tested", but won't clarify that they only ran the channel test, not the full patch testing. Patch testing is difficult to pass and more expensive, but legitimate manufacturers will do it because it ensures the cable conforms to standards and is worth what they are charging.

5. Misleading Cable Markings: All cables sold in the United States will use a UL "E-file Number" or the manufacturer's name and model number that you can look up on UL's database. The problem is that the marking may conform to UL's standard, but the cable may not. Again, a signed CoC will protect against counterfeits so make sure you get one!

6. Wire Gauge Changes: Often 25 or 26 AWG cables can be mislabeled as 24 AWG. If you require 24 AWG, you should always request a sample cable, cut it open, strip the insulation off of the wires and measure them. Don't trust a manufacturer that claims something they aren't selling; if they are untruthful about the wire gage, what else could they be hiding?

7. The Golden Sample: While it is a good idea to get a sample up front, many manufacturers will make a "golden sample" to be perfect for what you need, sometimes at great expense. When it comes time to manufacture the rest, they scrimp and cheat all they can to deliver under cost. You should always set up a system whereby you QC some of the cables in each shipment-and without the manufacturer's prior knowledge.
 
 
This problem is much more common than you think!
 
L-com found counterfeit cables from both big and small manufacturers, and from both domestic and oversea sources. “Made in the USA” means nothing if the cable is made with poor components in order to offer a cheaper price. If price is your priority, someone can always make a cheaper cable. It doesn’t matter where a cable is made, but how the cable is made.
 
The key is to know that your seller or manufacturer (like us!) is checking cable assemblies, insisting on proving UL compliance, testing their cables, and always meeting standards. At L-com our Ethernet cables are made in our own factory versus in a sub-contractor’s, guaranteeing superior quality every time. 
 

Tips for Buying Coaxial Cable

August 14, 2013 at 10:00 AM

 

What’s right for your application?

 

Selecting the proper coaxial cable can go a long way toward satisfying the needs of a specific application. Which criteria are most important to the specifying process? There are 4 key points to be considered when choosing coaxial cables:

 

      RG174/U Bulk Coaxial Cable - Flexible Small Diameter 50 Ohm Cable

 

 

 

 

 

 

1. Cable Type

 

There are basically two types of coaxial cables: those with an impedance of 75 Ohms (Ω), used mostly for video applications, and those with an impedance of 50 Ω, used mostly for data and wireless communications.

 

Typical 75 Ω cables are our RG59/U and RG6/U. These cable types are available in 100-, 500- and 1000-foot reels.

 

Typical RG-style 50 Ω cables for data are RG174/U, RG188/U and RG316/U. These bulk cables can be used in applications where cable assemblies must be built in the field. Available in 100-, 500- and 1000-foot rolls, their stranded 26 AWG center conductors result in very flexible cables for tight-fit applications. Additionally, the bulk RG188A/U cable has a Teflon-taped outer jacket to help achieve a 200-degree C operating temperature, and the RG316/U has an extruded FEP outer jacket that helps achieve a 200-degree C operating temperature.

 

50 Ω cables are also available in the low-loss version: 100-, 200-, and 400-series specifically for wireless applications. Low Loss coaxial cables provide far better shielding than their RG style counterparts and are best suited for RF applications.

 

 

2. Operating Frequency

 

Another important consideration is the operating frequency of the signal carried on the cable. As the frequency increases, the signal energy moves away from the cable's center conductor to the cable's shield outside of the conductor, a phenomenon known as the "skin effect".

 

This has a direct correlation to how far the signal can travel over a cable of a certain length, for a given signal frequency and power level. The higher the signal frequency, the shorter the distance traveled.

 

For our full Coaxial Cabling Tutorial, click here.

 

 

3. Cable Attenuation

 

Cable attenuation is the amount of signal loss over a specific distance. In general, the higher the frequency, the larger the attenuation will be. The larger the diameter of a cable's center conductor, the lower the attenuation is.

 

For example, an RG59/U cable with a 14 AWG center conductor can carry a signal (at a specific frequency and power level) about twice the distance as that of an RG11/U cable with a 20 AWG center conductor. It's imperative to know how much cable attenuation is acceptable in your particular application when selecting coaxial cable.

 

 

4. Characteristic Impedance

 

A coaxial cables characteristic impedance is an important parameter that affects the performance of the signal being carried over the cable. Also known as transmission impedance, it is defined as the relationship between a cable's capacitance per unit length to its inductance per unit length. For optimum signal transfer, the cable's characteristic impedance should be matched to the impedance/resistance of the load.

 

RG59A/U Bulk Coaxial Cable - Stranded Center Conductor 75 Ohm Cable
50 Ohm BNC Crimp Plug for RG58 - Amphenol #31-320-RFX
See a Matrix of Data
and Wireless Coax Cable Assemblies for Easy Ordering
Looking for bulk 75Ω cable for audio/video? See it here!
Get Coax Connectors
from L-com and build your own cable assemblies!
 
Quick note: RG-style coaxial cables are not all built the same. Check the specification requirements before you buy, and if you need help contact our technical support.
 

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.
 

Tutorial on Wireless Networking

June 12, 2013 at 10:00 AM

 

Wireless network antenna and devices

Entire cities and even countries are looking into ways to expand communications access for their residents as the Internet has shifted from a luxury to an imperative. The most promising solution: wireless networking.

 

Why? Wireless networking allows a non-physical (well, at least non-cabled) connection to a wireless LAN (WLAN) and onto the World Wide Web for users. So what are you waiting for? Cut the cord!

 

Be mindful of this though- issues such as network and band congestion, security, signal range and propagation, power demands, and more make WLANs tricky to implement for all but the most informed network engineers and IT professionals. Yet there's no stopping this technology in its rapid advance, with solutions such as distributed antenna systems (DAS) and MESH networks beginning to show promise. For you to get started, here's a basic wireless tutorial on terminology and concepts.

 


Wireless Standards

 

Radio frequency signals can take a lot of different forms, so in order for devices made by different manufacturers to communicate, the IEEE has provided several standards including the mainstay for wireless Ethernet: 802.11.

 

The 802.11 standard specifies the band and IP protocol used to transmit data, and provides guidelines to maximize the speed of transmission. 802.11a, for instance, uses the 5Ghz band and can typically transmit at speeds up to 54 Mbps in shorter ranges. 802.11b, 802.11g, 802.11n, and the new 802.11ac all use various methods to increase the speed and range. The latest IEEE wireless standard, 802.11ac boasts transmission speeds of up to 1 Gbps!

 

Each standard typically requires wireless routers, access points, and other transmission equipment to match its designation, though there are many that can operate in multiple standards (such as routers that are 802.11b/g/n compliant).

 


Wireless Bands

 

In attempt to maintain order within the entire radio frequency spectrum that is available to us, the FCC and other global communications standardization organizations have designated or set aside specific ranges of frequencies for specific uses. We call these "ISM bands". ISM stands for industrial, scientific and medical to denote where these frequencies are used.  ISM bands (specifically the 2.4 GHz and 5 GHz frequencies) are also used in commercial wireless networks. 

 

Typically access points, antennas, and amplifiers all use either the 2.4 GHz band, 5.8 GHz band, or both for WiFi. Other ISM bands have been set aside for things like cell phone use, RFID chips, emergency/municipal use, and military use.

 


Wireless Security

 

As mentioned previously, one of the big emerging issues with wireless networking is security. Without a physical cable that can be plugged and unplugged, the only method to control who can do what on a network is to build it into the software and protocol. That means it is critical to set up a wireless network with appropriate security measures and to be aware of the security status of any network you connect to.

 

For most small networks, methods such as WPA, WPA2, or WPA-PSK allow the safe identification of nodes that should be allowed on a network with passwords and other controls. Wireless routers can also use access passwords to allow administrators to adjust or update security features as required.

 
If you have questions about a wireless project or application, contact L-com's technical support line for a live response and expert advice!
 
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