Last year I was helping clean out my grandmother's garage and I came across a briefcase that my late grandfather used for one of his jobs. Inside was a bunch of manuals for industrial equipment from the mid 80s-early 90s and a couple of data tapes. I managed to transfer them and they are live at https://archive.org/details/TheDataTapeFiles. The problem is that I have no clue how to extract the data from the tapes.
I asked around and so far I gathered this information: the data itself is recorded at 300 baud and bursts at 12 second intervals, there is a carrier tone at about 2400hz that lasts for about four seconds and is quite unstable, and there is no filters done on the data itself. What makes this even harder is that a section of one of the tapes has been taped over with a recording of a loud machine. Luckily, the data track can still be heard so it may be recoverable. If anyone wants to mess with these recordings and see what you can make of them they are in that archive.org upload. Also audio warning for anyone who wants to listen to them. The first seven minutes of each tape are very loud and I think the way the tape drive was configured is to blame for that.
I asked around and so far I gathered this information: the data itself is recorded at 300 baud and bursts at 12 second intervals, there is a carrier tone at about 2400hz that lasts for about four seconds and is quite unstable, and there is no filters done on the data itself. What makes this even harder is that a section of one of the tapes has been taped over with a recording of a loud machine. Luckily, the data track can still be heard so it may be recoverable. If anyone wants to mess with these recordings and see what you can make of them they are in that archive.org upload. Also audio warning for anyone who wants to listen to them. The first seven minutes of each tape are very loud and I think the way the tape drive was configured is to blame for that.