A Multiple Rate Multiplexer for Use over the Dial Telephone Network

摘要

The design of a communications system to connect the Dartmouth-Thayer students in Jersey City with Dartmouth and the Dartmouth Time-Sharing System is discussed. It is found that a custom-designed system is less expensive than is modification of currently available systems. It is also found that even the commercially available systems with modification are much more economically attractive than is rental of additional telephone lines and equipment to do the same functions. A multiplex system, designed to meet the specification set on the system, is discussed. Certain problems noted during testing of the Modem printed circuit boards and not evident in the initial tests made on the bread board models, are investigated and the results are reported in Appendix 1. The findings tend to indicate that at the very least, major modification of the circuit boards are required and that total redesign of the circuits is probably in order to guarantee reliable data transmission. Uses of the system components other than in a multiplex system are discussed. Also discussed is modification of the original circuitry in order to produce a working multiplexer. (Author)