... ID
2 bytes: block length
2 bytes: pause after block ...
2 bytes: data length (or ... unlikely to me)
n bytes: the data itself

... ID x
2 bytes: block length
1 ... waves start positive.
2 bytes: actual data length
2 bytes: pause after block in ... ID y
2 bytes: block length
1 ... waves start positive.
4 bytes: actual data length

... stores them as Spectrum-files (BYTES on 1500 Baud).

... Block ID x
2 bytes: block length
1 ... waves start positive.
2 bytes: actual data length
... are zeroed.
2 bytes: pause after block in ms ... that deal with partial bytes do so in a ... any ZX81 files with partial bytes in?)

Or ...

... between them. 1s in the bytes sent to tape have a ...

... quite size-inefficient (about 10 bytes to represent one in the ...

I guess my information must be wrong. In that case, what's the adventage of using reti instead of ret? reti takes 2 bytes, and ret only 1.

... tap file that contains the bytes only. Tap files can easily ...

... lines be 9 numbers, 8 bytes plus checksum. Any of this ...

... other formats, eg separating the bytes with spaces similar to my ... the sum of the 8 bytes, isn't it? Even if ...