Similarly, if the Centre wished to communicate with a resident director, a postcard carrying microphotographs would be sent in the bag to the military attaché's office in a country adjacent to that in which the resident director concerned lived. This postcard the military attaché sent to an accommodation address in the resident director's country where it was collected by a courier and delivered to the chief cut-out, who in turn delivered it to the resident director. In all cases the occupiers of the accommodation or "cover addresses" concerned were entirely ignorant of the identity of the resident director, the military attaché, or even of the cut-outs who collected the mail. They usually believed that they were merely acting as accommodation addresses for the local Communist Party by whom they had probably been recruited.
Apart from this system of microphotographic communication, the networks also used a courier system. The resident director would send one of his trusted cut-outs to various fixed rendezvous in neighbouring countries where the cut-out would meet a courier from the Centre. This system, if slightly slower, was obviously better for the tranmission of bulky documents or samples of apparatus.
These two systems worked very well in times of peace, when postal communications were easy and rapid and, generally speaking, there was no systematic censorship of mail. In time of war, when communications were disrupted, at best subjected to long delay, and at worst never arrived at all, the system was clearly impracticable, and, saves over short distances, broke down. Even when it worked, all correspondence was liable to severe scrutiny by wartime censorship with the consequent risk of compromise.
As a result there was a radical reorganisation of communications systems, and now the main system in use is short-wave wireless transmission. This system is obviously infinitely quicker than the accommodation address and the numerous cut-outs and, provided normal precautions are observed, is equally safe.
In wartime it was vital that the Centre receive information as quickly as possible. Most of the information transmitted by networks concerned operational matters, and these would have been useless even if they had been subject only to the normal peacetime postal delays. As a result wireless transmission was instituted as the normal means of communication between the resident director and the Centre; and all resident directors are now required to undergo a course in radiotelegraphy and construction in Moscow before taking up the direction of a network abroad. Directors so qualified can send off urgent information as soon as it is encoded, without having to contact the normal wireless operator. If the director is forced to flee the country he can then build a new transmitter and is thus in a position to contact the Centre without the delays which a "place of conspiracy" or the contacting of a military attaché is bound to entail.
Though resident directors are now required to be so technically efficient, this newly acquired art has not taken away from the importance of the networks' wireless operators. Even if the director can transmit, it is obviously highly undesirable that in normal circumstances he should go to the set and do it himself- or worse still have the set in his house and transmit from there himself and thus imperil the whole network. As a result there is need for reliable wireless operators who will probably know the chief cut-out but will not know the identity of the director himself.
The ideal operator, like a resident director, is not a native of the country in which he is working. Through being a foreigner it is easier for him to hide his nocturnal and clandestine activities than if he were a permanent resident with many friends and relations all idly curious as to how he spends his time. In equally ideal circumstances this ideal operator will install himself and his transmitter in a top-floor flat of a large building situated in a built-up area. This makes it harder for direction-finding apparatus to locate him than if he were in an isolated place.
In peacetime the operator would probably have no more than two days a month when he was bound to establish two-way contact with the Centre. In addition there would also be several days each week when the Centre would be listening, at prearranged fixed times, in case he should call. Also on certain fixed days the operator himself would be required to listen in in case the Centre wished to call him.
In my network the Centre used a fixed call sign, though the call signs used by our sets varied according to a prearranged schedule. In order to establish communication a fixed call wave was used. For example, if
I wished to call the Centre I would tap out my call sign in Morse on my fixed call wave, say 43 metres. The Centre would be listening and reply on its fixed call wave, perhaps 39 metres. On hearing the Centre reply, I would then switch to my working wave length, say 49 metres, and then with a different call sign send over my material. The Centre would similarly switch wave lengths and call signs, and move over to their working wave length. This system, though it may sound complicated on paper, was simple to operate in practice and cut to the minimum the possibility of radio monitoring.