Recovering Cassette Tape Records

[Brent Hilpert]

Grant Stockly wrote:
> On top of all this, I'm having a hard time understanding the format.
> 
> This is a good line:
> 
>             1  2  3  4  5  6  7  8  9  10 11 12 13
> S1 13 0000 0D 76 00 F3 7E 18 F9 7E 03 3C 00 00 48 38 00 2C 7E
> 
> S1 means its a data record,
> 13 is the byte count,
> 0000 is the address,
> and 7E is the checksum.
> 
> So what are the mystery bytes?  How do you get 13 data bytes and still have
> a place for all of the rest?  13 is supposed to include the checksum!  The
> checksum is the one's compliment of the sum of the all bytes except S1 and
> the checksum itself.
> 
> FF-(13+0D+76+F3+7E+18+F9+7E+03+3C+48+38+2C)=7E
> 
> So 7E is the checksum.  I want to know where all those bytes go!  :(

Can't help you with the tape read problem although the speed issue as you
suggest sounds like a good guess, but as for the 
byte count issue: it's 13 hex = 19 dec, which works out exactly for the line
you show when you include the address bytes (everything after the 13).

Lesson: you're up too late at night :)  ...but then so am I (!) :/