wˌɛn ðə bˈɑːks ɪz ˈæktᵻvˌeɪɾᵻd baɪ tˈɜːnɪŋ ɐ nˈɑːb ɔːɹ pˈʊlɪŋ ɐ hˈʊk, ɐ spɹˈɪŋlˈoʊdᵻd wˈiːl tˈɜːnz, tˈæpɪŋ ˈaʊt ɐ pˈʌlst ᵻlˈɛktɹɪkəl sˈɪɡnəl kˌɔːɹɪspˈɑːndɪŋ tə ðə bˈɑːksᵻz nˈʌmbɚ.
When the box is activated by turning a knob or pulling a hook, a spring-loaded wheel turns, tapping out a pulsed electrical signal corresponding to the box's number.