What is data cable?
Data cable is used to connect your phone with PC for communication through COM port. Just as cable printer, hardware to connect your printer with PC. Cables for mobile phones are connected via Serial RS-232, LPT1 DB25 printer cable or USB.
What is the difference between Cat3, Cat5, Cat5e, Cat6, etc.?
This is actually a somewhat complex question to answer as it involves a number of technical details. The most basic answer is that each Category of cable is supposed to meet (or exceed) a specific set of standards, the most significant of which, is the ability to pass all signals up to a particular carrier frequency (or signaling rate). Additional standards have to be met include values for attenuation, near end cross talk (NEXT), ACR, etc.
Below is a table of the types of Category Cable we install. The table shows the Maximum Carrier Frequencies required by the EIA/TIA 568 Standards for each category of cable and the Maximum Frequencies the manufacturer actually tests the cable to.
| Catgory |
Typical Applications |
Frequency Required |
Tested To |
EIA/TIA Ratified Standard? |
| Cat 3 |
Voice |
16 MHz |
16 MHz |
Yes |
| Cat 5 |
Voice, Data (10/100 Mbps Ethernet) |
100 MHz |
100 MHz |
Yes |
| Cat 5e |
Voice, Data (10/100 Mbps/ Gigabit Ethernet) |
100 MHz |
200 MHz |
Yes |
| Cat 6 |
Voice, Data (10/100 Mbps/ Gigabit Ethernet) |
200 MHz |
500 MHz |
Yes |
What do you recommend installing for our Ethernet network?
In most circumstances we currently recommend Cat 5e. The 5e product we use has been tested by the manufacturer to the 200Mhz level which will leave adequate bandwidth for current and future applications while helping to keep installation costs down. However if cost is less of an issue and you're seriously concerned with higher data rates for future applications then we would recommend Cat 6.
Can Cat 5e/Cat 6 works with our existing Cat 5 patch panel?
Yes, BUT if different category components, such as a patch panel or a jack are used with a higher category component such as a higher level of cable then your data lines will only perform to the level of the lower category device. So if you used Cat 6 cable with a Cat 5 patch panel you should only expect to get Cat 5 performance. For optimum performance ALL components (data cable, patch panel, jack, and patch cables) must be of the same Category level.
I have offices that are a good distance from the telco closet, what is the maximum length a Category 5/5e/6 cable can be and still work?
According to the EIA/TIA-568 standards the end-to-end connection between network devices should not exceed 100 meters (328 feet). Note that 100 meters is total length including all patch cables. Officially no one single line from a patch panel to the outlet in the work area should exceed 90 meters (294 feet) so that you have length to spare (10 meters) for the patch cables running from the outlet to your computer and from the patch panel to your switch or hub.
I need both voice and data cable installed; is there any advantage to installing Cat 5e or Cat 6 for my phone system?
Cat 5e or 6 installed for both your data and phones offers you the flexibility to use your phone jacks as network jacks in the future (assuming you have the cables terminated onto a patch panel). If you use Cat 3 for your phones then your future use of those cables will be pretty much limited to that purpose. Note that while the price differential between Cat 3 and Cat 5e/6 is getting slimmer the one disadvantage is still that a Cat 5e or 6 installations will still be more expensive.
Why do I need all the bandwidth of category 6? As far as I know, there is no application today that requires 200 MHz of bandwidth.
Bandwidth precedes data rates just as highways come before traffic. Doubling the bandwidth is like adding twice the number of lanes on a highway. The trends of the past and the predictions for the future indicate that data rates have been doubling every 18 months. Current applications running at 1 Gb/s are really pushing the limits of category 5e cabling. As streaming media applications such as video and multi-media become commonplace, the demands for faster data rates will increase and spawn new applications that will benefit from the higher bandwidth offered by category 6. This is exactly what happened in the early 90's when the higher bandwidth of category 5 cabling compared to category 3 caused most LAN applications to choose the better media to allow simpler, cost effective, higher speed LAN applications, such as 100BASE-TX. Note: Bandwidth is defined as the highest frequency up to which positive power sum ACR (Attenuation to Crosstalk Ratio) is greater than zero.
What is the general difference between category 5e and category 6?
The general difference between is in the transmission performance, and extension of the available bandwidth from 100 MHz for category 5e to 200 MHz for category 6. This includes better insertion loss, near end crosstalk (NEXT), return loss, and equal level far end crosstalk (ELFEXT). These improvements provide a higher signal-to-noise ratio, allowing higher reliability for current applications and higher data rates for future applications.
Will category 6 supersede category 5e?
Yes, analyst predictions and independent polls indicate that 80 to 90 percent of all new installations will be cabled with category 6. The fact that category 6 link and channel requirements are backward compatible to category 5e makes it very easy for customers to choose category 6 and supersede category 5e in their networks. Applications that worked over category 5e will work over category 6.
What does category 6 do for my current network vs. category 5e?
Because of its improved transmission performance and superior immunity from external noise, systems operating over category 6 cabling will have fewer errors vs. category 5e for current applications. This means fewer re-transmissions of lost or corrupted data packets under certain conditions, which translates into higher reliability for category 6 networks compared to category 5e networks.
When should I recommend or install category 6 vs. category 5e?
From a future proofing perspective, it is always better to install the best cabling available. This is because it is so difficult to replace cabling inside walls, in ducts under floors and other difficult places to access. The rationale is that cabling will last at least 10 years and will support at least four to five generations of equipment during that time. If future equipment running at much higher data rates requires better cabling, it will be very expensive to pull out category 5e cabling at a later time to install category 6 cabling. So why not do it for a premium of about 20 percent over category 5e on an installed basis?
What is the shortest link that the standard will allow?
There is no short length limit. The standard is intended to work for all lengths up to 100 meters. There is a guideline in ANSI/TIA/EIA-568-B.1 that says the consolidation point should be located at least 15 meters away from the telecommunications room to reduce the effect of connectors in close proximity. This recommendation is based upon worst-case performance calculations for short links with four mated connections in the channel.
What is a "tuned" system between cable and hardware? Is this really needed if product meets the standard?
The word "tuned" has been used by several manufacturers to describe products that deliver headroom to the category 6 standard. This is outside the scope of the category 6 standard. The component requirements of the standard have been carefully designed and analyzed to assure channel compliance and electrical/ mechanical interoperability.
What is impedance matching between cable and hardware? Is this really needed if product meets the standard?
The standard has no impedance matching requirements. These are addressed by having return loss requirements for cables, connectors, and patch cords.
Is there a use for category 6 in the residential market?
Yes, category 6 will be very effective in the residential market to support higher Internet access speeds while facilitating the more stringent Class B EMC requirements (see also the entire FCC Rules and Regulations, Title 47, Part 15). The better balance of category 6 will make it easier to meet the residential EMC requirements compared to category 5e cabling. Also, the growth of streaming media applications to the home will increase the need for higher data rates which are supported more easily and efficiently by category 6 cabling.
Why wouldn't I skip category 6 and go straight to optical fiber?
You can certainly do that but will find that a fiber system is still very expensive. Ultimately, economics drive customer decisions, and today optical fiber together with optical transceivers is about twice as expensive as an equivalent system built using category 6 and associated copper electronics. Installation of copper cabling is more craft-friendly and can be accomplished with simple tools and techniques. Additionally, copper cabling supports the emerging Data Terminal Equipment (DTE) power standard under development by IEEE (802.3af).
What is meant by the term "Electrically Balanced"?
A simple open wire circuit consisting of two wires is considered to be a uniform, balanced transmission line. A uniform transmission line is one which has substantially identical electrical properties throughout its length, while a balanced transmission line is one whose two conductors are electrically alike and symmetrical with respect to ground and other nearby conductors.* "Electrically balanced" relates to the physical geometry and the dielectric properties of a twisted pair of conductors. If two insulated conductors are physically identical to one another in diameter, concentricity, dielectric material and are uniformly twisted with equal length of conductor, then the pair is electrically balanced with respect to its surroundings. The degree of electrical balance depends on the design and manufacturing process. Category 6 cable requires a greater degree of precision in the manufacturing process. Likewise, a category 6 connector requires a more balanced circuit design. For balanced transmission, an equal voltage of opposite polarity is applied on each conductor of a pair. The electromagnetic fields created by one conductor cancel out the electromagnetic fields created by its "balanced" companion conductor, leading to very little radiation from the balanced twisted pair transmission line. The same concept applies to external noise that is induced on each conductor of a twisted pair. A noise signal from an external source, such as radiation from a radio transmitter antenna generates an equal voltage of the same polarity, or "common mode voltage," on each conductor of a pair. The difference in voltage between conductors of a pair from this radiated signal, the "differential voltage," is effectively zero. Since the desired signal on the pair is the differential signal, the interference does not affect balanced transmission. The degree of electrical balance is determined by measuring the "differential voltage" and comparing it to the "common mode voltage" expressed in decibels (dB). This measurement is called Longitudinal Conversion Loss "LCL" in the Category 6 standard. * The ABC's of the telephone Vol. 7
What is the difference between enhanced category 5e cable rated for 400 MHz and category 6 cable rated for 250 MHz?
Category 5e requirements are specified up to 100 MHz. Cables can be tested up to any frequency that is supported by the test equipment, but such measurements are meaningless without the context of applications and cabling standards. The category 6 standard sets minimum requirements up to 250 MHz for cables, connecting hardware, patch cords, channels and permanent links, and therefore guarantees reasonable performance that can be utilized by applications.
Why did all category 6 cable used to have a spline, and now is offered without one?
Some category 6 cable designs have a spline to increase the separation between pairs and also to maintain the pair geometry. This additional separation improves NEXT performance and allows category 6 compliance to be achieved. With advances in technology, manufacturers have found other ways of meeting category 6 requirements. The bottom line is the internal construction of the cable does not matter, so long as it meets all the transmission and physical requirements of category 6. The standard does not dictate any particular method of cable construction.
Is there a limitation on the size of bundles one can have with category 6? Can you have 200-300 and still pass category 6?
There is no limit imposed by the standards on the maximum number of category 6 cables in a bundle. This is a matter for the market and the industry to determine based on practical considerations. It should be pointed out that after six or eight cables, the performance in any cable will not change significantly since the cables will be too far away to add any additional external (or alien) NEXT.
Will contractors be able to make their own patch cords?
Category 6 patch cords are precision products, just like the cables and the connectors. They are best manufactured and tested in a controlled environment to ensure consistent, reliable performance. This will ensure interoperability and backward compatibility. All this supports patch cords as a factory-assembled product rather than a field-assembled product.
Do you have to use the manufacturer's patch cords to get category 6 performance?
The category 6 standards have specifications for patch cords and connectors that are intended to assure interoperable category 6 performance. If manufacturers can demonstrate that each component meets the requirements in the standard, minimum category 6 performances will be achieved. However, manufacturers may also design their products to perform better than the minimum category 6 requirements and in these cases compatible patch cords and connectors may lead to performance above the minimum category 6 requirements.
Why do field tester manufacturers offer many different link adapters if everyone meets the standard?
This was an interim solution while the standard was still being developed and the interoperability requirements were not yet established. It is likely that soon one or more adapters will work for testing of cabling from all vendors.
Would you get passing test results if you used a link adapter not recommended by a manufacturer?
You should expect to get passing results if both the link adapter interface and the mating jack that is part of the link are both compliant to category 6 requirements.
Are the connectors for category 5e and category 6 different? Why are they more expensive?
Although category 6 and may look alike, have much better transmission performance. For example, at 100 MHz, NEXT of a category 5e connector is 43 decibels (dB), while NEXT of a category 6 connector is 54 dB. This means that a couples about 1/12 of the power that a couples from one pair to another pair. Conversely, one can say that a category 6 connector is 12 times less "noisy" compared to a category 5e connector. This vast improvement in performance was achieved with new technology, new processes, better materials and significant R&D resources, leading to higher costs for manufacturers.
What will happen if I mix and match different manufacturers' hardware together?
If the components are category 6 compliant, then you will be assured of category 6 performance.
What basic steps can I take to prevent my house from being burglarized?
Think of your home as a box and the doors and windows as being openings to that box. Burglars will enter through doors or windows accessible from the ground. Just closing and locking these accessible openings when you're away is a basic burglary prevention step. As a rule of thumb, all doors should be made out of solid core wood or be metal-clad to prevent or delay forced entry. All exterior doors should be equipped with heavy-duty deadbolt locks supported by heavy-duty four-screw strike plates fastened with three-inch wood screws solidly into the door frame. Exterior doors should have a peep-hole viewport to see who is outside before opening. Accessible sliding glass windows and doors should have secondary security devices to prevent forced entry or lifting the window pane out if its track. See Burglary Prevention Advice for more details.
. My house has been burglarized three times in two years, how can I stop this?
Obviously, burglars are attracted your home either because of its isolated location, your lifestyle, or the way you secure the home. Simply stated, your home has burglar curb appeal and appears to be an easy target on your block. You can change this by fortifying doors and windows (see Burglary Prevention Advice), installing an alarm system and use it, and examine your lifestyle. For example, if you are gone a lot you should set up a relationship with neighbors to watch over your home, and pick up newspapers. If you are gone at night, install light timers to turn on interior lights or the television to simulate occupancy. Don't leave windows, doors, or garage doors open while away and lock side gates. Use alarm signs and beware of dog signs.
Do home alarm systems prevent break-ins?
In a word, yes. Basic home alarm systems are designed to detect unauthorized entry and evidence of fire and report it…that's it. It's the fear of detection and reporting that prevents burglaries. Reporting consists of a loud bell or siren that sends most burglars running or the option of having the signal monitored by an external alarm company that will notify whomever you request. To keep burglars out, you need to warn them first of the existence of your alarm system by using a lawn sign and window decals of the alarm company. Of course, for all this to work the homeowner needs to incorporate the use of the alarm system into their everyday routine and actually use it.
What kind of alarm system should I get to protect my home?
The brand name doesn't matter as long as it's good quality. Alarm systems use basic electronic components and wiring and works using a series of open and closed electronic switches. A hard-wired system is the most reliable for a newly constructed single family home. Each door and window alarm contact is supported by its own pair of wires back to the alarm panel and can be isolated as the exact point of entry. Hard-wired system wiring and door and window contacts are imbedded into the door and window frames and thereby protected from tampering. See my Home Alarm Systems webpage.
A less-expensive retro-fit solution will use wireless technology to transmit a radio-frequency signal back to the alarm panel instead of by wire. The wireless devices are battery operated and therefore are larger and mounted externally on the door or window point of entry. They are cheaper and easier to install, but suffer from issues of tampering, battery failure, and radio frequency (RF) signal interference. Budget usually dictates what system is appropriate for your home. Wireless works great in rental housing.
What features should I look for in a home alarm system?
Alarms systems vary dramatically with add-on options much like buying a new car. For most people the basic alarm package is good enough. The basic system provides door and window alarm contacts on all openings, one or more infra-red motion sensor inside, an audible horn or siren, and a control panel with a digital dialer and keypad. Beyond the basic alarm system you can add hard-wired smoke and heat detectors, glass break detectors, ultra-sonic and infra-red motion sensors, temperature sensors, shock sensors, control panel tamper sensors, battery back-up, and cell phone signal reporting technology. I've seen upscale homes with sensors monitoring the temperature in wine cellars and caviar refrigerators.
Must I have my burglar alarm monitored by a security company to be effective?
No, the local horn or siren works well enough to dissuade most burglars. Program the siren to reset after 30 seconds. However, if you want the police or fire department to be called in your absence then a monitored system is the only way to go. Be advised that most insurance companies require a monitored alarm system for discounted fire insurance rates.
Do iron grills or bars on windows stop burglars?
Besides being ugly and a radical security measure, window grills definitely work to prevent entry through accessible windows. To be effective, the grills need to be made of substantial material and fastened with non-removable screws that cut deeply into the window frame. Be aware that the US Fire Code prohibits putting bars on windows in sleeping rooms unless there is a proper release mechanism inside or two points of escape.
Will metal security screen doors prevent forced entry into my home?
Metal screen doors with a deadbolt lock definitely add another layer of protection to the home. They are installed on top of the door frame and swing outward making it more difficult to force entry. These screen doors are good for homeowners who routinely leave their front door open for ventilation. These doors should not be relied upon for high security because the screen can be easily compromised and expose the deadbolt latch.
I've heard that guard dogs are effective in preventing break-ins, is that true?
Yes, burglars hate guard dogs. Dogs are noisy and can attract unwanted attention. Large guard dogs are potentially dangerous to intruder. Because of this fear, "Beware of Dog" signs posted on a gate or fence can be very effective in keeping burglars off your property.
Can automatic garage door opener signals be read by criminals with scanners?
This is largely an urban myth, although it is technically possible. Automatic garage door openers use remote controls that send out radio frequencies (RF) to activate the garage door opener. It is possible for a burglar to read this RF code as you enter your driveway and push the transmitter button. The crook would have to be in very close proximity (right behind you) to capture this signal with the right equipment and knowledge how to use it to open your garage door in your absence. A criminal with this much talent could probably find a real job somewhere. Fortunately, most quality garage door openers now have a RF signal scrambler feature that uses a random RF signal for each opening and thereby defeats the risk of code copying and use.