Wednesday 5 December 2018


"Concluding Statement on Proving Grounds Trials of the TPU-3M tank intercom device produced by V.I. Lenin factory #197
October 9th, 1940

The commission, consisting of [names and titles] came to the following conclusions after conducting proving grounds trials:
  1. The TPU-3M prototypes meet the tactical-technical requirements set by the US and ABTU.
  2. The TPU-3M intercom device allows very satisfactory communications via radio between KV tanks at expected ranges between KV tanks both while stationary or during movement in 1st, 2nd, or 3rd gear, and satisfactory communication in 4th gear.
  3. No difference could be detected when comparing the legibility of transmissions made through the tank radio directly and those made through the TPU-3M intercom device.
  4. The TPU-3M intercom allows tank crews to communicate with each other in 1st, 2nd, and 3rd gear and is satisfactory in 4th gear (some words had to be repeated).
  5. The TPU-3M intercom meets the requirements for use in tanks in terms of simplicity and reliability. The use of an MA type microphone with an activation button is difficult for the crew, especially the driver.
  6. The commission tested two angled differential throat microphones produced at factory #197 with the TPU-3M. Communication between the commander and radio operator at all speeds was satisfactory. Communication between two tanks, both in motion and stationary, was satisfactory. The commission considers it necessary to use throat microphones with the TPU-3M device.
  7. Acoustic interference in the KV tank make it necessary to connect the commander and the gunner with an intercom, as voice communication between them is difficult. NIST and factory #197 provided a layout that can provide a connection for a fourth member (gunner) to the TPU-3M device, which gave good results both in motion and while stationary. The commission considers it sensible to add the fourth member of the KV tank crew to the intercom.
  1. The commission considers that the TPU-3M tank intercom device produced by factory #197 can be put into production in 1940 after correction of defects.
  2. The commission considers that in 1941 production the TPU-3M intercom device should be equipped with a throat microphone, for which factory #197 must design a new throat microphone based on the samples tested by the commission.


  1. Thanks! I always find these little technical pieces interesting.

    We forget how many little technologies were just emerging as the Second World War broke out (before the beginning of the GPW). Small things like having an intercom make an immense difference in the ability of the tank commander to actually command the crew. Even more so, communication could be two-way. Before intercoms, it was often impossible for the driver to tell the commander anything at all!

  2. And yet we still encounter people who insist Soviet tanks had no intercoms and the TC directed the driver via kicks. I like asking those folks how that worked in the SU-76.......

    1. Probably something like this:

    2. Well, there were thousands of tanks used during the GPW that worked just that way. Heck, someone on another forum just related that he used that method as an M113 commander in the 80s.

      The British ended up sending a lit of tanks into combat without radios because they industry couldn't keep up with tank production. I have no doubt that intercom production fell short in the Soviet Union at times, especially in the early war, and that long transportation distances and factory relocations to escape the Nazis caused both supply chain delays and reductions in output.

      It's possible that some T-34s only had two crew intercoms if microphone/earphone production fell short. Better to kick the units out the door with only two sets attached than to completely choke off the supply.

      You might think that it's silly to imagine headphone production falling behind production of the central electronic box (can't think what it's called!), but earphones need all sort of little things.

    3. I don't doubt that.

      I am simply saying I encounter people who insist that NO Soviet AFV had intercoms or radios.

    4. Such people are blithering idiots and should be treated as such. Pointing them at photos of prewar stuff with those conspicuous horseshoe antennas at the back of the turret optional...

  3. That's interesting article, because in Poland, in many articles, I see information that early T-34 have only 2 tankers connected to intercom. And we see that's propably untrue information. Also many years ago I suspected that's not true that T-34 have only 2 tankers connected to intercom, because in english translated T-34 manual I see information about 3 tankers intercom (and in this manual is also information about more advanced intercom with 4 tankers connected).BTW, propably in Poland we have situation that many authors revrited informations, without serious research.