Add signal regeneration and signal extension equipment – The comments regarding amplifiers apply here as well. This however, requires volumes of auxiliary equipment, a myriad number of cross wiring points, and extensive record-keeping. Add amplifiers to power the voice signal on long loops.Increase battery voltage – This violation of operating standards could pose a safety hazard.The heavy-gauge cables yielded far fewer pairs per cable and led to early congestion in cable routes, especially in bridge crossings and other areas of limited space. Use heavy-gauge conductors – Up to 19 gauge (approximately the gauge of pencil lead), which is costly and bulky.A variety of schemes were implemented before DLC technology to offset the impedance long loops offered to signalling and volume levels. There is also a minimum power level required to provide adequate volume for the voice signal. A minimum current of around 20 mA dc is required to convey terminal signalling information to the network. Electric current values vary with cable length and gauge. When the subscriber goes off-hook, a cable pair behaves like a single loopinductance coil with a -48 V dc potential and an Electric current of between 20–50 mA dc. Long loops, such as those terminating at more than 18,000 feet (5.49 kilometres) from the central office, poseelectrical challenges.
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