OK on the FR-300, I'm not familiar with that particular m/c, but the FR series were analogue instrumentation recorders.
I think they would have been similar to the Honeywell 7600 series which I worked on at Zonal films in the 60's. They were multitrack recorders generally 1/2" or 1" with up to 16 tracks, they were multi speed from 1-7/8 ips- 120ips and had very accurate capstan servos with vacuum bins for supply and take up tension control.
You could record audio or data with normal a/c bias or FM saturation record. I seem to remember that at the max speed you could record up to about 1.5MHz with a 3dB roll off.
Coo that brought back some memories.