Difference between Ethernet cables ?

Difference between Ethernet cables?

Not all Ethernet cables are the same, so what is the difference, and how do you know which you should use? In this short guide we take a look at the technical and physical differences between the Ethernet cables available on broadband buyer.

Ethernet cables are grouped into sequentially numbered categories (e.g CAT5) based on different specifications; sometimes the category is updated with further clarification or testing standards (e.g. CAT5e, CAT6a). These categories are how we can easily know what type of cable we need for a specific application. For our IP Surveillance ( IP Camera, Access Control, BAS, Intrusion ... etc) CAT6 is recommended to install, including PoE based design. 

Manufacturers are required to adhere to the standards which makes our lives easier.

CAT Technical differences

The difference in Ethernet cable specification is not as easy to see as physical changes; so let’s look at what each category does and does not support. Below is a chart for reference when picking cable for your application based on the standards for that category.

Difference between Ethernet cables
	Length	10Mb/s	100Mb/s	1GbE	10GbE	PoE	Mhz
CAT5	100	Y	Y			Y	100
CAT5e	100	Y	Y	Y		Y	100
CAT6	100 (55 for 10GbE)	Y	Y	Y	Y	Y	250
CAT6a	100	Y	Y	Y	Y	Y	500

You may notice that as the category number gets higher, so does the speed and Mhz of the wire. This is not a coincidence, because each category brings more stringent testing for eliminating crosstalk (XT) and adding isolation between the wires.

Category 5 cable was revised in 2001, and mostly replaced with Category 5 Enhanced (CAT5e) cable which did not change anything physically in the cable, but instead applied more stringent testing standards for crosstalk. Category 6 was revised between 2002 with Category 6 Augmented (CAT6a) in 2008 that provided testing for 500 Mhz communication (compared to CAT6 - 250 Mhz). The higher communication frequency eliminated alien crosstalk (AXT) which allows for longer range at 10 GB/s.

Physical Differences

So how does a physical cable eliminate interference and allow for faster speeds? It does it through wire twisting and isolation. Cable twisting was invented by Alexander Graham Bell in 1881 for use on telephone wires that were run along side power lines. He discovered that by twisting the cable every 3-4 utility poles, it reduced the interference and increased the range. Twisted pair became the basis for all Ethernet cables to eliminate interference between internal wires (XT), and external wires (AXT).

There are two main physical differences between CAT5 and CAT6 cables, the number of twists per cm in the wire, and sheath thickness.

Cable twisting length is not standardised but typically there are 1.5-2 twists per cm in CAT5(e) and 2+ twists per cm in CAT6. Within a single cable, each colored pair will also have different twist lengths based on prime numbers so that no two twists ever align. The amount of twists per pair is usually unique for each cable manufacturer.

Many CAT6 cables also include a nylon spline which helps eliminate crosstalk. Although the spline is not required in CAT5 cable, some manufacturers include it anyway. In CAT6 cable, the spline is not required either as long as the cable tests according to the standard.

The nylon spline helps reduce crosstalk in the wire, with the thicker sheath protecting against Near End Crosstalk (NEXT) and Alien Crosstalk (AXT), which both occur more often as the frequency (Mhz) increases. In this picture below, the CAT5e sheath has the thinnest sheath versus CAT6 but it also was the only one with the nylon spline.

Shielded (FTP) vs. Unshielded (UTP)

Because all Ethernet cables are twisted, manufacturers use shielding to further protect the cable from interference. For example, Unshielded Twisted Pair (UTP) can easily be used for cables between your computer and the wall but you will want to use Foil Shielded Cable (FTP) for areas with high interference and running cables outdoors or inside walls.

There are different ways to shield an Ethernet cable, but typically it involves putting a shield around each pair of wire in the cable. This protects the pairs from crosstalk internally. Manufacturers can further protect cables from alien crosstalk with additional cable shielding beneath the sheath. The diagram below shows the different types of Ethernet shielding and the codes used to differentiate them.

Difference between Optic Modem and Media Converter

Difference between Optic Modem and Media Converter

Fiber Optic Modem

Fiber Optic Modem, also known single-port optic multiplexer, is a point-to-point type terminal equipment which uses a pair of optic fibers to achieve the transmission of E1 or V.35 or 10base-T. Fiber modem has the function of modulation and demodulation. Fiber modem is local network relay transmission equipment, suitable for base station transmission fiber terminal equipment and leased-line equipment.

Fiber modem is similar to the baseband MODEM (digital modem). The only difference from baseband MODEM is that it access fiber line, the optical signal. The multi-ports optic transceiver generally called multiplexer. For multi-port optical multiplexer is normally be directly called “multiplexer”, single-port multiplexer is generally used on the client, similar to commonly used WAN line (circuit) networking with the baseband MODEM, and also named for “fiber modem”, “optical modem”.

Fiber Media Converter

Fiber Media Converter is a simple networking device making the connection between two dissimilar media types become possible. Media converter types range from small standalone devices and PC card converters to high port-density chassis systems that offer many advanced features for network management.

Fiber media converters can connect different local area network (LAN) media, modifying duplex and speed settings. Switching media converters can connect legacy 10BASE-T network segments to more recent 100BASE-TX or 100BASE-FX Fast Ethernet infrastructure. For example, existing half-duplex hubs can be connected to 100BASE-TX Fast Ethernet network segments over 100BASE-FX fiber.

When expanding the reach of the LAN to span multiple locations, media converters are useful in connecting multiple LANs to form one large campus area network that spans over a limited geographic area. As premises networks are primarily copper-based, media converters can extend the reach of the LAN over single-mode fiber up to 160 kilometers with 1550 nm optics.

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Wavelength-division multiplexing (WDM) technology in the LAN is especially beneficial in situations where fiber is in limited supply or expensive to provision. As well as conventional dual strand fiber converters, with separate receive and transmit ports, there are also single strand fiber converters, which can extend full-duplex data transmission up to 120 kilometers over one optical fiber.

Other benefits of media conversion include providing a gradual migration path from copper to fiber. Fiber connections can reduce electromagnetic interference. Also fiber media converters pose as a cheap solution for those who want to buy switches for use with fiber but do not have the funds to afford them, they can buy ordinary switches and use fiber media converters to use with their fiber network.

Main Difference between Media Converter And Optical Modem

The difference between the media converter and optical modem is that the media converter is to convert the optical signal in the LAN, simply a signal conversion, no interface protocol conversion. While, fiber modem for WAN is the optical signal conversion and interface protocol conversion, protocol converter has two types of E1 to V.35 and E1 to Ethernet.

In fact, as the developing of network technology, the concept of media converter and fiber modem has become increasingly blurred, which are basically can be unified for the same equipment. Media converter becomes the scientific name of fiber modem.

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Few things need to know, There are two primary types of fiber optic cable, single mode fiber (SMF) and multimode fiber (MMF). The former has a very thin core about 5-10 microns in diameter, which is about 10 percent of the latter. Generally, single-mode optical fibers used in telecommunications operate at 1310nm or 1550nm wavelength while multimode fiber at 850nm and 1300nm. However, sometimes, the subdivision of the two types is different due to various fiber optic cable manufacturers. single mode optical fiber cable is used for longer distances such as 100km compared with multimode fiber under 2km due to the smaller diameter of the fiber core. Therefore, single mode optical fibers are typically used outside between buildings in cable TV, internet, and telephone signals transmission while multimode fibers are used within buildings in backbone applications such as computer network linking.

Normally, fiber optic cable speed rates at 10 Gbps, 40 Gbps and even 100 Gbps.

Generally, one fiber optic cable is made up of incredibly thin strands of glass or plastic known as optical fibers (called “core”) surrounded by an insulated casing (called “cladding). Each strand is a little thicker than a human hair and can carry much data like 25,000 telephone calls. Therefore, an entire fiber optic cable can easily carry as much data as you can imagine.