Years ago, I used a 300 baud modem to encode "log book" information on one track of a 7 track 1/2" tape recorder along with 6 vibration data tracks for machinery condition analysis. The encoded track identified what machine the data was from, the measurement locations for each channel, all the gain settings for each channel and the FFT analysis ranges required for each channel.
When the data was played back, a modem read the data track, recovered all the log book information and then cycled the tape back and forth to produce the required FFT spectral plots. It was amazing to watch the first reel of tape being analyzed! Instead of a tedious manual process, the tape cycled back and forth a number of times for each recording and spectral graphs started pouring out of the plotter. A typical vibration survey's data reduction time was reduced from 3 man-weeks to 8 hours! All that was needed was somebody to change tape reels as each one was completed to keep the process moving along.
300 baud isn't a very fast data rate but it was way more than needed to encode the necessary information for each one minute recording. In processing thousands of data recordings, I can only recall a few that couldn't be read back reliably. It was an extremely reliable system.
One additional features was very nice. Each recording required several pieces of information and when writing that information in a log book, crucial information could be missed. With a computer writing the information to tape, it forced filling in all the blanks before the recording would start.
I encoded the data in formatted ASCII text rather than trying to compress it in any way. That way, any modem and terminal could be used to view the data encoded on the tape. Not specific program was required to convert the data into a viewable format if there was any question about it.