Coaxial cable can be divided into baseband coaxial cables and broadband coaxial cables from the main purpose. Coaxial cable is divided into two categories: 50Ω baseband cable and 75Ω broadband cable. The baseband cable is divided into a thin coaxial cable and a thick coaxial cable. The baseband cable is only used for digital transmission with a data rate of up to 10Mbps.

    Coaxial cable refers to a cable with two concentric conductors, and the conductor and the shield are the same axis. The most common rf coaxial cable consists of a copper conductor insulated with an insulating material. Outside the inner insulating material is another layer of loop conductor and insulator, and then all the cables are covered by a sheath of polyvinyl chloride or Teflon material.

    Coaxial cables can be divided into two main types, baseband coaxial cable and broadband coaxial cable assembly. Now the baseband is a commonly used cable. The shielded wire is made of copper and has a characteristic impedance of 50 (such as RG-8, RG-58, etc.). The common shield of the wideband coaxial cable is usually made of aluminum. Stamped, the characteristic impedance is 75 (such as RG-59, etc.).

    Coaxial cables can be divided according to their diameter: thick coaxial cable and thin coaxial cable can be used for large and medium-sized local networks. It has a long standard distance and high reliability because it does not need to disconnect the cable during installation. The specific location of the computer can be flexibly adjusted according to the need, but the transceiver cable must be installed in the thick cable network, and the installation difficulty is large, so the overall cost is high.

    The installation of the thin cable is very simple and the cost is low. However, because the cable is disconnected during the installation process, the basic network connector (BNC) must be installed on both sides, and then connected to both sides of the connector, so it is very easy to cause a problem when the connector is long. Hidden danger, it is one of the most mechanical failures caused by Ethernet in operation today.

    Both the thick cable and the thin cable are bus topologies, that is, one cable is connected to multiple machines. This type of topology is suitable for machine-intensive environments. However, when a common fault occurs at a contact point, the fault will be connected to the whole. All the machines on the cable. The diagnosis and recovery of common faults is cumbersome and will gradually be replaced by unshielded twisted pair or fiber optic cable.