This standard is applicable to subscriber telegraph and low-speed data communication network, which uses frequency modulation to open 50 bits/second data. This standard stipulates the tolerance of various damage factors of the transmission path that is allowed to guarantee the transmission quality of 50 bits/second channel reporting data.
GB/T 4827-1984 history
1984GB/T 4827-1984 Requirements of data transmission at 50 bit/s