The equipment in the communication industry generally uses -48V DC power supply, and the anode is grounded. Why? First, historical reasons In the era of fixed telephone, the telephone of every household is powered by the office of telecommunication bureau. Because the distance between the telecommunication bureau and the telephone in the home is relatively […]
The equipment installation height in the 19-inch standard cabinet is expressed by a special unit “u”, with 1U=44.45mm U refers to the effective use space inside the cabinet, and the panels of standard equipment using 19-inch standard cabinets are generally manufactured according to the specifications of n u. For some non-standard equipment, most of them can be installed and fixed in a 19-inch chassis through additional adapter baffles. The panel width of most engineering-grade equipment is 19 inches, and the installation hole distance is 465 mm. Therefore, as long as the cabinet can meet the installation requirements of most 19-inch equipment, the cabinet is a standard cabinet.
1. please describe the relationship between optical cable, optical cable section and optical fiber core? Answer: The communication between the two network elements is connected by optical fiber, and the optical cable is in the optical cable. Because the distance between the two network elements is too far and one optical cable is not long […]
IP is an acronym for Ingress Protection. The IP rating is the needle bai for electrical equipment housing stoking foreign body du, the zhi source is the International Electrotechnical Commission standard IEC 60529. This standard in dao 2004 was also adopted as the United States national standard . In this standard, for the protection of […]