Blowing machines are specially designed for blowing telecommunication and data transmission cables in pre-installed channels and are also suitable for blowing subducts. The system operates on the viscous drag principle, employing compressed air to install the cable, controlled and assisted by a belt drive system. The cable is propelled by compressed air and fed into the duct, while the hydraulically powered belt drive system controls the fiber optic cable. The electronic monitoring system reads out speed and distance, provides protection against duct or cable obstructions and includes an emergency stop facility.