I'm probably equally rusty, but I believe ",8,1" loaded programs written in machine language, and ",8" was for BASIC programs (at least that's what I recall doing). So it looks like the port was written in BASIC.
,0 The program will be loaded to the start of BASIC memory (2049/$0801)
,1 The program will be loaded absolute, i.e. to its stored location defined by the first two bytes in the binary file. Needed for machine language programs.
So you could also load binary programs from cassette with a LOAD "*",1,1