Cassette BASIC question

[MoonHound]

I have a cassette with an old program from high school written on a TI 99 /
4 (which is not available to me now). How could I retrieve it? Maybe I
could record it into a wav file. I have some old version of BASIC on hand
that might be compatible, QuickBasic and VBDOS. But how would I import the
sound file into them or change it back to code? Thanks.

[Dick Grier]

Hi,

Tricky.

This files used FSK (Frequency Shift Keying) encoding at 300 baud (usually),
and if the data is ASCII, not binary, you MAY be able to recover it. If I
recall, a "1" would be 1200 Hz, and a "0" would be 600 Hz, with standard
8-bit serial format (1 start, 8 data, 1 stop, and no parity). If so, then
it would be possible to record this to a wave file and to write a program to
decode the FSK.

I haven't done it, but this might get you started.

BTW, I did design a simple circuit that did this decoding more than 25 years
ago. Its output was serial RS-232, and functioned because the encoding was
as I described above. I haven't seen the board that I designed in recent
years, and don't have a copy of the schematic, so my memory is my only
resource.

Dick