In common with OKW/Chi, the Army Signal Intelligence Service (known as Inspectorate 7/VI until the reorganization of 1944, thereafter known as OKH/GdNA, the Oberkommando  ders Heeres/General der Nachrichten Autklaerung) had its common roots in the pre-Hitler era Code and Cipher section of the Defense Ministry. By 1934 the Defense Ministry had 10 fixed intercept stations scattered across Germany. Their mission was the interception and cryptanalysis of foreign military communications, along with the interception of some diplomatic traffic.

With the creation of OKW, the Armed Forces High Command, the SIGINT Service was split into two agencies, OKW/Chi, and a service for the OKH (the Army) which eventually became GdNA. This was a large organization, numbering over 12,000 personnel by the height of the war, many of them assigned to GdNA’s extensive tactical field based interception and analysis units.

By the mid point in the war, the OKH SIGINT service central organization was composed of three branches. IN 7/VI, the central cryptanalytic bureau headquartered near the Bendlerstrasse in Berlin; a central evaluation agency.  It was commanded in the first part of the war by Major Mettig. In November 1943, the first large raid of the RAF on Berlin destroyed a great part of the offices of OKW, including those of IN 7/VI, forcing them to move to Juerbourg, until it was consolidated shortly afterwards.  The LNA, which was dedicated to analysis of traffic from numerous nations including the USA, Britain, Italy, the Balkans, located at Zossen had a comparatively small staff of only 75.  Thirdly, from 1941, a center dedicated to the analysis of Russian traffic, the Intercept Control Station East (HLS Ost) was created and located in Loetzen,  East Prussia, commanded by Colonel Kettler, who later became chief of OKW/Chi.  Due to bombings and retreats, the three centers reorganized and centralized into one agency for cryptanalysts and evaluation in October 1944 with the formation of the GdNA, under the command of Colonel Boetze.

     KONA’s 1,2, and 3 were stationed on the eastern front covering the northern, central and southern Army Groups. Later KONA 6 was created to cover the Caucasus. New KONAs were formed or existing ones moved as the strategic situation changed when new fronts were created by Allied invasions and the Germans were put on the defense. KONA 7 formed in February 1943 to cover the Italian front and after the invasion of France, KONA 6 was moved west to join KONA 5. Later two new KONAs were created to augment the eastern front, KONA 8 and KONA Nord.

The Army put much effort into the interception of Russian traffic with all these KONAs assigned to the eastern front, including a special detachment in Finland. Following their traditional offensive philosophy, these units operated as far forward as was practical, with one regiment, KONA 3 caught in a pocket and captured intact by the Russians in 1945.  Although successful in reading many low-grade Soviet systems, TICOM concluded that the majority of the German SIGINT success on the eastern front was a result of skillful use of traffic analysis.

On the Western Front, coverage was concentrated initially on Allied traffic originating from the British Isles, Iceland and the continental United States.  During the Norway campaign Army cryptanalysts captured a copy of the British War Office code and successfully read this code from 1941 until 1943. IN 7/VI also expended a great deal of effort to solve the British high level system TYPEX, but made little progress, finally abandoning the effort sometime in 1943.  In North Africa, a Long Range SIGINT company, FAK 621 provided tactical and strategic intelligence to General Rommel and was a key factor in his early victories in the campaign. The company, overrun and captured by New Zealand troops at the battle of Tell el Eisa in July 1942, was a crippling blow to Rommel after which his success in the desert steadily declined. After D-Day, the emphasis naturally shifted to coverage of British, American and French traffic emanating from the front.

As for their efforts against the Americans, a number of 4-figure administrative codes used primarily in traffic from Iceland or the Mediterranean were solved. Early in the war, they broke an old US Army code named M-94, purely through mathematical analysis. However TICOM reports that ‘…after the solution had been achieved cryptanalytically, a USA manual (FM 11-5) with a complete description of the M-94 was found in a Berlin library.’ The successor to the M-94 was a Hagelin type machine called the M-209, solved by the Germans in the autumn of 1943. This medium level code represented the outstanding success of IN 7/VI against the Americans. Captured codebooks containing M-209 settings proved to be of great tactical value, and the M-209 keys of the 82^nd and 101^st Airborne divisions were captured during the D-Day invasion, allowing the Germans to read six days worth of Allied traffic.  In all, TICOM estimated that the Germans were able to read 10% of the M-209 generated traffic in the European Theater.

Typical was KONA 1, formed early in the war to monitor Russian communications from its fixed stations at Konigsberg, Warsaw, and Berlin. In 1940, the unit moved west to cover the British broadcasts during the French campaign, and then returned east to Lancut, Poland. They covered the central part of the eastern front until the fall of Berlin, and then they retreated west.

 Major Ernst Hertzer commanded the unit, which in 1945 consisted of some 700 officers and enlisted men and women. Retreating in May of 1945, they destroyed most of their papers except for the most essential, and surrendered after VE day upon encountering American troops. They were taken to the PW cage of the 16th Armored division at Konstantinovy Lazne, Czechoslovakia, where they were discovered by TICOM Team 2 on 23 May. There all the remaining members of the regiment initially interrogated for five days and a further 41 were moved to a camp at Revin, France. The prisoners were cooperative and for the next month, they wrote reports and were interrogated in depth, resulting in the bulk of information that TICOM developed about German Army SIGINT.