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1.什么是56Kbps 调制解器技术?传统的调制解调器技术是通过公共电话网(PSTN)实现对调制解调器两端的模拟连接。当信号发送时,模拟信号被转为数字信号,而信号到达接收端时又被转回模拟信号。模拟到数字的转换过程产生“e”信号,并因此把传输速度限制在33.6Kbps 之内。目前的公共电话网(PSTN)的核心已经升级为数字方式,仅有5-6km 部分的电信网络(本地环路)仍采用模拟线路。由于大多数的 ISP 及在线服务供应商采用数字线路(T1、E1、ISDN、PRI 等)将他们的网络接入服务器(NAS),这就减少了一条模拟环路,或是模拟到数字的转换。因此,只要网络接入服务器一端为数字式的并且是端到端56Kbps 协议兼容,用户就可以通过现有的 PSTN,以56Kbps 的速度下载文件。请注意,采用56Kbps 技术,下行速度为56Kbps,上行速度仍为33.6Kbps。
1. What Is 56Kbps Modem Technology? Conventional modem technology is an analogue connection to both ends of the modem via the public switched telephone network (PSTN). When the signal is sent, the analog signal is converted to a digital signal and the signal is turned back to the analog signal when it reaches the receiving end. The analog-to-digital conversion produces an “e” signal and therefore limits the transmission speed to 33.6Kbps. The core of the current Public Switched Telephone Network (PSTN) has been upgraded to digital mode, with analogue lines still being used in telecommunications networks (local loops) of only part of 5-6km. Because most ISPs and online service providers use their digital network (T1, E1, ISDN, PRI, etc.) to connect their network to a server (NAS), this reduces the number of analog loops or analog to digital conversions . Therefore, as long as the network access server is digital and end-to-end 56Kbps compatible, users can download files at 56Kbps over the existing PSTN. Please note that with 56Kbps technology, the downlink speed is 56Kbps and the uplink speed is still 33.6Kbps.