Text on the front cover of a red coloured folder: Instructions for acceptance (delivery and servicing) of the telephone exchange systems MEK8 and BOA-12; of the command bunker DIOGANES near Arnhem (Arnheim) in Holland (Kommando-Bunker)


These kinds papers are extremely rare, as they have survived the German deliberate destructions of this huge Bunker complex, which was meant for air-defence control in a sector of western Europe

We have to apologize for the sometimes poor quality of reproductions. One have to take into account, that the paper sheets were victim of heavy cordite smoke and dust, though, also due to its wartime paper quality. A friend of mine has captured these papers, among other things, in 1945. Entering the Bunker premises with a torchlight and crumbling over all the rubbish around (sometimes in danger of falling down into wide gaps in the floors, owing to the explosions) . When his torch would have failed, he might not have found his way back. He probably was one of the first who entered this dangerous site. The Germans even had exploded heavy bombs inside the building, as to destroy as much as possible of its inventory.


Front panel of the AEG 8 channel carrier-telephone apparatus (multiplex) type MEK8. This photo does not originate from the Dioganes site


Alignment data of the telephone carrier systems MEK8 and BOA-12 in the Dioganes Bunker site

Until now I always thought that the BOA-12 systems were originally of German design. This document gives, however, the impression that it originate from Bell Telephone Mfg. Co. Antwerp, Belgium. As according to the acceptance calibration information, Bell Telephone had delivered this system to the German air defence, about 1942.



Two adjustment tables of the BOA-12 carrier-telephony system inside the Dioganes bunker near Schaarsbergen in the Netherlands

Please click on the two tables as to open it in your computer browser

Please consider again that the reproduction quality is a compromise between the intense black parts of the documents and its readability


Calibration table 1 (PDF) size A3

Calibration table 2 (PDF) size A3


The last paragraph of this document (Anhang D) might contain interesting information, as is stated:

Bemerkung: Da die verwendeten Röhren erst seit kurzer Zeit vom jetzigen Lieferanten gefertigt werden, sind diese Grenzen als vorläufig zu betrachten. Sie können gegebenenfalls, nach gesammelter Erfahrung geändert werden.

What did they actually mean? Did they dealt with the Siemens long-life valves type E2e or C3e? When this was the case, there might be an interesting implication, which have to be dealt with in due course. Does anyone reading these lines have any additional information on what valve (tube) types were used in conjunction with BOA-12 systems?


Please contact us, when you have photos of BOA-12 and MEK8 or other related information:




Label of the telex storage cupboard (Fernschreibgeräte-Vorratsschrank) Bauart: Luftnachrichtenzeugamt Teltow; Gerät-Nr. 124-3324A-1; Werknummer (serial number) 10-41, where 10 might be meant cupboard serial-number 10 and 41 the year of its production. GAF signals part number: Ln17026-3; manufacturer Lemke K.-G. in Berlin


We recently received Helmut Schicke's contribution on: German Carrier Telephony Systems, BOA12 - MEK8 and MG15

PDF 1.4 MB



Go back to, or proceed with: BOA12-Schicke page

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