Teletypes were commonly used with the less-expensive computers from Digital Equipment Corporation (DEC); these systems had to use what keys were available, and thus the DEL character was assigned to erase the previous character.
tˈɛlᵻtˌaɪps wɜː kˈɑːmənli jˈuːzd wɪððə lˈɛsɛkspˈɛnsɪv kəmpjˈuːɾɚz fɹʌm dˈɪdʒɪɾəl ɪkwˈɪpmənt kˌɔːɹpɚɹˈeɪʃən dˌiːˌiːsˈiː; ðiːz sˈɪstəmz hædtə jˈuːs wʌt kˈiːz wɜːɹ ɐvˈeɪləbəl, ænd ðˈʌs ðə dˌiːˌiːˈɛl kˈæɹɪktɚ wʌz ɐsˈaɪnd tʊ ᵻɹˈeɪs ðə pɹˈiːviəs kˈæɹɪktɚ.