Unless I got the string wrong and it is EXACTLY "t=00 b=000 r=00 st=00000 sp=00000"

Then I would try something like:

SERIN2 1,N2400,[SKIP2, DEC 2 T, SKIP 3, DEC3 B, SKIP 3, DEC2 R, SKIP 4, DEC5 ST, SKIP 4,DEC5 SP]


So, that should skip the "t=" grab the 00 into T, skip the " b=" grab the 000 into B, skip the " r=" grab the 00 into R, skip the " st=" grab the 00000 into ST, skip the " sp=" grab the 00000 into SP

Once again the numerical sizes would apply as would the experimenting.
Anyway, that's where I would start playing.