Coaxial cable can be divided into two basic types, baseband coaxial cable and broadband coaxial cable. The baseband is commonly used in the cable, shielded wire is made of copper mesh, the characteristic impedance is 50 (RG-8, RG-58); the shielding layer of cable broadband coaxial cable used for aluminum stamping is usually the characteristic impedance is 75 (such as RG-59).
Coaxial cable can be divided into coarse coaxial cable and fine coaxial cable according to its diameter. Thick cable suitable for local network is relatively large, it is the long distance, high reliability, because the installation does not need to cut off the cable, so it can be flexibly adjusted according to the needs of the computer network, but the network must install thick cable transceiver cable, the installation is difficult, so the overall cost is high. On the contrary, thinnet installation is relatively simple, low cost, but the installation process is to cut off the cable ends shall be installed on the basic network connector (BNC), and then connected at both ends of the T connector, so when the joint long prone to adverse risks, this is one of the most common fault current in the operation of the ethernet.
Whether or thinnet thick cable are the bus topology, which is a cable connected with the machine, this machine is suitable for dense topology environment, but when a contact failure, failure will affect the whole series of all machines on a cable. Fault diagnosis and repair are very troublesome, so will be gradually replaced by unshielded twisted pair or optical cable.