A small portable selfcontained device that simulates data communications control functions, evaluates system performance, and isolates equipment failures.It is intended for testing of either asynchronous or synchronous modems in simplex, halfduplex, or fullduplex mode. It determines the overall condition of a data channel consisting of a telephone line with a modem at each end.This type of tester transmits a 511bit pseudorandom test pattern and measures the biterror rate of the received signal.; 一個(gè)小型攜帶式的獨(dú)立裝置,可以模擬數(shù)據(jù)通信控制功能、估價(jià)系統(tǒng)性能以及查找設(shè)備 故障。其目的在于檢測(cè)單工、半雙工或雙工通信方式下的異步或同步調(diào)制解調(diào)器。它用 來(lái)測(cè)定由電話線及其兩端的調(diào)制解調(diào)器組成的數(shù)據(jù)信道的全部情況。這種檢測(cè)器 發(fā)送一個(gè)511位的偽隨機(jī)測(cè)試編碼并測(cè)量接收信號(hào)的誤碼率。