I worked on the very first fibre-optic transatlantic cable, TAT-8, which had the enormous capacity of 280Mbp/s on two fibre pairs. Later I worked on PTAT-1 and TAT-9, which had double the capacity with four fibre pairs. At that time the primary use was carrying voice circuits. I also worked on NPC, a trans-pacific cable, probably the first cable to have a business case on data traffic use - mainly fax!