If you need to decode in real time I would still input a single string up to the CR/LF and then split the string.
Other way would be to input one character at a time. If it's not a comma then add it to a string. If it's a comma chuck it into the next string. Hmmm....that's a pretty poor way to explain things. Something like
DIM bytestr AS STRING * 1
DIM fin$(5)
' set up your port# (port$) and speed (comms$) here
I=0
OPEN "COM" + port$ + ":" + comms$ + ",N,8,1,BIN,CS0,DS0" FOR RANDOM AS #1
IF LOC(1) THEN
GET #1, , bytestr
IF (bytestr <> ",") THEN fin$(I) = fin$(i)+bytestr
elseif (bytestr = ",") then I = I+1
endif
endif
fin$(4) will contain 48*FF so you'll have to split that.
That probably won't work as I've been working with PHP for the last few days and I keep getting the syntax mixed up but the basic idea is there.