Office Connect ISDN LAN Modem

hello and this is sunny welcome back today my topic is our SDM integrated services Digital Network not a long time ago the pstn was all analog from customer premises to central office local loop and from central office to the backbone of the network PSTN was simply designed for analog telephone calls with the advent of the personal computers digital data transmission was needed for voice cause everything remained the same for computers modems were developed to allow the decoy exchanges over existing analog PSTN Network digital signals are modulated to analog signals and it transmitted over the PSTN Network only at the receiving end analog signals are D modulated back to original digital signals but analog signals have many disadvantages compared with digital signals one over the long-distance analog signals cannot maintain high quality to analog signals carried less information per seco