Anglo-Canadian transatlantic telephone cable (CANTAT). Repeaters and equalization

The paper describes the repeaters and equalization methods used on the CANTAT submarine telephone system between Oban (Scotland) and Corner Brook (Newfoundland). In contrast to previous submerged repeaters, a new valve was used in the amplifiers and the voltage drop across a repeater was about 70V¿a reduction of some 40% despite this, the greater number of repeaters in the cable increased the line voltage supply considerably, and the repeaters were designed to withstand a higher voltage between the inner unit and its housing. Because of the larger number of repeaters and greater difficulty in locating faults, a new supervisory method was adopted which could also locate noise faults. The equalizers, besides having basic networks, allow mop-up equalization to be performed on board ship during the lay.