A high performance ISDN/ATM multimedia integrated access system(THMAS 1) for real time interactive distance learning is proposed in this paper. It consists of remote access units and a central access/switching dev...A high performance ISDN/ATM multimedia integrated access system(THMAS 1) for real time interactive distance learning is proposed in this paper. It consists of remote access units and a central access/switching device. At the subscriber side, the ISDN PRI interface operating at E1 line rate (2.048Mb/s) is provided directly to the termination. When the transmission medium is double of twisted pair cable which has the specification of 0.6mm/22AWG, the longest transmission distance can come to 2.6km. One remote access unit has the capacity of equivalent accessing port of 256 E1s, and the typical capacity for whole THMAS 1 system is 30720 E1 ports. Optical fiber transmission link is adopted between the remote access unit and the central device, and the peak transmission distance under no relay can reach out 60km. To the network direction, a standard ATM UNI interface at STM 1 rate (155.520Mb/s) is designed, so an ISDN/ATM hybrid access system can be constructed. THMAS 1 has the capability of n× 64kb/s (1≤n≤30) ISDN time slots conformance switching, and has the features of small volume, low power consumption, low cost, flexible to reconstructing the network as well as wide coverage of geographical access space. So it is especially suitable for the real time interactive remote teaching.展开更多
文摘A high performance ISDN/ATM multimedia integrated access system(THMAS 1) for real time interactive distance learning is proposed in this paper. It consists of remote access units and a central access/switching device. At the subscriber side, the ISDN PRI interface operating at E1 line rate (2.048Mb/s) is provided directly to the termination. When the transmission medium is double of twisted pair cable which has the specification of 0.6mm/22AWG, the longest transmission distance can come to 2.6km. One remote access unit has the capacity of equivalent accessing port of 256 E1s, and the typical capacity for whole THMAS 1 system is 30720 E1 ports. Optical fiber transmission link is adopted between the remote access unit and the central device, and the peak transmission distance under no relay can reach out 60km. To the network direction, a standard ATM UNI interface at STM 1 rate (155.520Mb/s) is designed, so an ISDN/ATM hybrid access system can be constructed. THMAS 1 has the capability of n× 64kb/s (1≤n≤30) ISDN time slots conformance switching, and has the features of small volume, low power consumption, low cost, flexible to reconstructing the network as well as wide coverage of geographical access space. So it is especially suitable for the real time interactive remote teaching.
