At the time, computers used tubes and were not reliable enough to control a phone system (phone system switches are safety-critical, and they are designed to have an unplanned failure about once per thirty years).
U to vreme, računari su koristili vakuumske cevi i nisu bili dovoljno pouzdani da kontrolišu telefonski sistem (prekidači telefonskog sistema su kritični po pitanju sigurnosti i dizajnirani su tako da imaju neplanirano otkazivanje, otprilike jednom u trideset godina).