A coial cable("co" in English) is a cable composed of two coial, mutually insulated cylindrical metal conductors to form a basic unit (coial pair), thiabthen a single or multiple coial pairs. It has been used to transmit data thiabvideo signals for a long time.
It is one of the first media to support 10BASE2 thiab10BASE5 Ethernet, which can achieve 10 Mb/s transmission up to 185 meters or 500 meters, respectively. The term "coial" means that the central conductor of the cable thiabits shield have the same axis or center point. Some coial cables may have multiple shielding layers, such as a four-shielded coial cable, which contains two layers of shielding, thiabeach layer of shielding is composed of aluminum foil wrapped with wire mesh. The shielding characteristics of coial cable make it have strong anti-electromagnetic interference ability thiabcan transmit high-frequency signals over long distances. There are many different types of main types of coial cables that support a wide range of professional applications, such as satellite communications, industrial, military thiabmarine applications. The three most common types of non-industrial coial cables are RG6, RG11thiabRG59, ntawm uasRG6yog feem ntau siv nyob rau hauvCCTV thiabCATVdaim ntawv thov nyob rau hauv tuam txhab ib puag ncig. Qhov chaw pib ntawmRG11yog thicker tshajRG6, which means that its insertion loss is lower thiabthe signal transmission distance is longer.
Txawm li cas los xij, thickerRG11 kab hluav taws xob are more costly thiabvery difficult to bend, which makes them unsuitable for deployment in internal applications, but more suitable for long-distance outdoor installations or straight backbone links. RG59yog ntau saj zawg zogRG6, but its loss is higher. It is rarely used in other applications except for low-bandwidth, low-frequency analog video applications (rear-view cameras in automobiles) with short distances thiablimited wiring space. Coaxial xaim hluav taws xob also have different impedances-usually 50, 75, thiab93 ΩCov. 50.Ω coial cables have high power handling capabilities thiabare mainly used in radio transmitters such as amateur radio equipment, civil bthiabradio (CB) thiabwalkie-talkies. 75 Ω cables can maintain signal strength well thiabare mainly used to connect various types of receiving equipment, such as cable television (CATV) receivers, high-definition televisions thiabdigital video recorders. 93 Ω Coaxial cable was used in IBM mainframe networks in the 1970s thiabearly 1980s, with very few applications thiabexpensive. Although the 75 Ω coial cable impedance is most commonly encountered in most applications today, it is important to note that all components in the coial cable system should have the same impedance to avoid possible signal loss thiabsignal loss at the connection point. Internal reflections that reduce video quality. The digital signal 3 (DS3) signal used in the central office (also known as T3 line) transmission service also uses coial cables, including 75 Ω 735 type thiab734 type. The 735 type cable has a coverage distance of 69 meters, while the 734 type cable has a coverage distance of 137 meters.RG6 cablekuj tseem siv tau los xa cov cim DS3, tab sis cov kev pab cuam nrug deb dua.