'modem-controlled' originates from the combination of 'modem' and 'controlled', where 'modem' is derived from 'modulator-demodulator', and 'controlled' is from the Latin 'contrarotulare', meaning 'to check or regulate'.

'modem' evolved from the need to modulate and demodulate signals for communication, while 'controlled' has been used in English since the 14th century to denote regulation or command.

Initially, 'controlled' meant 'to check or regulate', and this meaning has largely remained the same in modern usage.