GB/T 7255-1998 in English

《GB/T 7255-1998单边带电力线载波机》由TC82（全国电力系统管理及其信息交换标准化技术委员会）归口，主管部门为中国电力企业联合会。
本标准适用于通过高压电力线传输信息的单边带(SSB)电力线载波机(PLC)。本标准的目的是规定单边带电力线载波机输入输出特性的建议值，并为理解这些建议给出定义说明。检验要求的各项试验应为国际电工词汇定义的型式试验（IEV151-04-15）。

Scope

This standard applies to single sideband (SSB) power line carriers (PLCs) that transmit information over high voltage power lines. The purpose of this standard is to specify recommended values for the input and output characteristics of SSB power line carriers (Figure 1) and to give definitions for understanding these recommendations. All tests required for inspection shall be type tests defined by the International Electrotechnical Vocabulary (IEV 151-04-15). This standard gives the following definitions for power line carrier transmitters in two different application modes: ——Basic carrier transmitter standard terminal The audio side is a carrier transmitter with a frequency band of 300Hz-3 400Hz four-wire interface and a signaling interface (Figure 2). This carrier machine can be connected to a communication network composed of different equipment produced by different manufacturers through an analog interface. Point-to-point paths (for example, teleprotection paths) outside the 300Hz-3 400Hz frequency band may be attached to the equipment. ——Multiple carrier machine speech-plus terminal The audio side is a carrier machine with multiple interfaces such as telephone, data, and remote protection (Figure 3). Part of the two types of carrier is common. See 5.2 and 5.3.1 for the requirements of common parts.