Sunday, April 27, 2014

Various kinds network cable

Network cable can be classified into coaxial cable, twisted pair, and optical fiber cable. 

1,Coaxial cable: it’s a kind cable with core copper wire shielded  by insulative layer, which have a capacity
of tough disturbance resisting, stable data transmitting, low price; and I must mention this kind cable also been used for closed circuit TV. The coaxial cable should be used together with BNC Connector, but customer can ask the factory supply cable assembly which the BNC connector already connected with the raw cable wire.

2, Optical fiber cable: it’s the fastest cable been used today, but its price are high, very rare been used in household places. It’s a kind cable consisted of hair-like glass fiber shielded with insulation layer. Rely on optical pulses to transmit data, Optical fiber cable have an extremely strong resistance to interference, high security for data transmission, high speed, large data transmitting capacity. Below, I will introduce the difference between single-mode optical fiber and Multi-mode optical fiber.

(1Multimode optical fiber.

In multimode optical fiber, the data are transmitted through more than one route, it often been used within a mile’s distance, as the effective distance from transmitter to receiver is about 5miles; furthermore, stronger the source light, more sensitive the receiver, larger distance will be achieved. Our research tells the bandwidth of multimode optical fiber is about 4000Mb/s; single mode optical fiber is used to avoid pulse broadening, the minimum size of fiber core (7-9μ) avoided the jump pulse from side to side. When we use a confocal laser in a wavelength of 1310 and 1550, we see the laser going directly into the tiny fiber core and to be transmitted to the receiver without apparent jumping.

2single-mode optical fiber
Single-mode optical fiber have a thinner fiber core, the optical pulses can be transmitted directly to the center of the core. Single-mode optical fiber often been utilized in a longer distance. The signal lost by single-mode optical fiber is lower than a multi-mode optical fiber, for example, in a distance of 3000 feet, multi-mode optical fiber would lose 50% of its signal strength, but for single-mode optical fiber, only 6.25%.The potentiality of Single-mode optical fiber made the only choice for us to employ it in long distance and high speed data transmission. Our recent test point out, a 40G 64 Ethernet information channel can be transmitted as long as 2840 miles. In safe application, the common determining factor for us whether to choose single-mode optical fiber or multi-mode optical fiber is distance: longer distance above 5 miles normally made a choice of single-mode optical fiber; multi-mode optical fiber is used within a 5miles distance, however, the bandwidth should not ignored, we should choose single-mode optical fiber if the future transmission include large bandwidth signals.

3. twisted pair:
Twisted pair is two cable wires stranded together, the standing can make electromagnetic waves neutralized between two wires, can resist outside electromagnetic interference. Twisted pair has a limited transmitting distance, information channel width, and transmitting speed comparing with other transmitting medium, but have a relatively lower price.

The most commonly used twisted pair cables are: CAT3, CAT5, CAT5E and CAT6, the former have thinner diameter, while the later have thicker diameter.

(1)   CAT1, this is a kind cable mainly used to transmit sounds, not for transmit data. The standard of Cat1 is mainly used for telephone in the beginning of eighties.

(2)CAT2, The frequency for this type is 1MHZ, used for sound transmitting and transmitting a low data not more than 4Mbps.The application of CAT2 commonly seen in 4Mbps token passing protocols based old token-ring network

(3)CAT3,This is a kind prescribed cable used in ANSI and EIA/TIA568 protocol, having a transmitting frequency of 16MHz,CAT3 are used for sound transmitting and 10Mbps data transmitting and below. Mainly used for 10BASE—T.

(4)CAT4, with a transmitting frequency of 20MHz, this kind cable mainly used for sound transmitting and data transmitting in 16Mbps and below, used mainly in Token Ring based local area network (LAN) and 10BASE-T.

(5)CAT5, this kind wire increased winding thickness, clad with a kinds of high quality insulation material, Cat5 have a transmitting rate of 100MHz, used for sound transmitting and data transmitting in 100Mbps and below. Cat5 is the most commonly used Ethernet cable for 100BASE-T and 10BASE-T internet.

(6)CAT5E, it’s a kind cable with low attenuation and lesser crosstalk, a higher attenuation to crosstalk ratio
and higher Signal-to-noise ratio, low time-delay errors, greatly improved the performance. CAT5E is mainly used for billibit Ethernet (1000Mbps)
PS:the higher the attenuation to crosstalk ratio (ACR) for a given cable, the less chance of signal errors, the higher the Signal-to-noise ration means less distortion.

(7)CAT6, with a transmit frequency of 1MHz-250MHz, cat6 wiring system should have a relative larger margin for general attenuation-to-crosstalk ratio in 200MHz,it provides 2 times bandwidth than CAT5E. The transmitting performance of CAT6 is high above the standard of CAT5E, which made it most suitably for a application with a transmitting rate above 1Gbps.A big difference for CAT6 comparing with Cat5e is the improvement on the aspect of crosstalk and return loss; cat6 canceled the basic link model but adopted star-shaped topological structure, requesting the cabling distance of a permanent link within 90m and information channel length within 100m.

(8)CAT6E, This is an updated version of cat6, belongs to a kind of Unshielded Twisted Pair (UTP) under the standard of ANSI/EIA/TIA-568B.2 and ISO 6/E, mainly used in Gigabit Ethernet.CAT6E have the same transmitting frequency with CAT6, i.e. 200-250MHZ, the largest transmitting speed of CAT6E is 1000Mbps.Comparing with CAT6, CAT6E greatly bettered the aspects in crosstalk, attenuation, and signal-to-noise ratio (SNR).

(9)CAT7, this is an updated twisted pair under the standard of ISO7/F, mainly for the application and development of 10 Gigabit Ethernet. But, it no longer belongs to a kind of unshielded twisted pair (UTP), but kind of shielded twisted pair (STP).CAT7 has a transmitting frequency above 500MHz, 2 times than CAT6 and CAT6E, and 10Gbps’transmittiong rate.

PS: STP is shielded with aluminum foil, it can reduce radiation, but cannot completely remove it, STP have a higher price than UTP, and installation will not be so easy as UTP, mostly we suggest customers buy UTP for it have advantages such as: Saving space for its smaller diameter, lesser weight, easy bent, easy installation, reduced the crosstalk to the minimum, fire resistance, independent and flexible, suitable for structured and integrated wiring.

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