I just won these: and I'm now not so sure they were a smart purchase :)
They have two 7-pin chassis-mount "slightly military style" connectors, and another identical connector on a short captive cable. I had assumed they were simply ruggedized cassette mechanisms with an interesting input, but now I received them I realize they have a bunch of switch settings and apparently several recording channels - not just the usual 4.
Does anyone have some concrete idea what these are - PWM recorders? I want to use them to record an audio-type signal. The cassette thus produced doesn't need to be compatible with any other recording device. Teac's aerospace site suggests this was designed for medical and vehicular telemetry gathering, but they have no data on this specific model.