Phantom Ciruits (1 янв 1921 г. – 31 дек 1921 г.)
Описание:
The switching of large numbers of calls was made possible through the use of phantom circuits. This allowed three conversations to take place on two pairs of wires.Добавлено на ленту времени:
Дата:
1 янв 1921 г.
31 дек 1921 г.
~ 12 months