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.