The mission was intended to last for 2 years, and called for information to be communicated to Germany by morse code radiotelegraphy using a shortwave radio transmitter the agents were expected to build. In the event they could not transmit by radio, they were to send the information via postal letters written in secret ink and addressed to a number of "mail drops", which included both American prisoners of war and intermediaries in Spain. It was thought that the agents would eventually build additional shortwave radio transmitters for use of other German agents sent to the United States in the future.