A digital modem and analogue modem pair for use on the Public Switched Telephone Network (PSTN) at data signalling rates of up to 56 000 bit/s downstream and up to 33 600 bit/s upstream
一种数字调制解调器和模拟调制解调器对 用于公共交换电话网(PSTN) 下行数据信令速率高达56000位/秒 上行数据信令速率高达33600位/秒