Technical Services for Mine Communications Research. Task D:Applicability of Available Multiplex Carrier Equipment for Mine Telephone Systems.

摘要

Available analog and digital telephone multiplexing equipment is investigated for its potential to upgrade the traffic handling capacity of present mine phone systems and provide for selective calling. The assessment includes the impact on and constraints imposed by overall mine communications,safety regulations,present mine pager phones and phone line networks,potential interference from trolley wire communications,pager phone interfacing and line conditioning requirements,and cost. A 'representative mine'in a communications sense is formulated to serve as a common basis for system and cost comparisons. The investigation reveals that only two or three frequency multiplexed subscriber carrier systems can be considered as serious condidates. However, a more detailed assessment of their practicality for a hypothetical mine installation indicates that even these candidates are largely unsuitable for most underground coal mines,thus requiring the development of special multiplex systems or the use of multipair cable to obtain more channels. The practicality and cost of installing multipair cable in underground mines is also assessed.