You could set up a retry loop.

mainloop:
High led
pause 250
low led
pause 250

for I=1 to 5 'or anything you like
Owout ibutton,1,[$33],mainloop
pause 100
owin ibutton,0,[Serial[0],Serial[1],Serial[2],Serial[3],Serial[4],Serial[5],Serial[6],Serial[7]]
If Serial[1]=$15 and Serial[2]=$D3 and Serial[3]=$7D AND Serial[4]=$16 AND Serial[5]=$00 AND Serial[6]=$00 then correct1
If Serial[1]=$68 and Serial[2]=$36 and Serial[3]=$4F AND Serial[4]=$17 AND Serial[5]=$00 AND Serial[6]=$00 then correct2
If Serial[1]=$1E and Serial[2]=$1A and Serial[3]=$2C AND Serial[4]=$17 AND Serial[5]=$00 AND Serial[6]=$00 then correct3
Next i
'If Serial[1]=$F0 and Serial[2]=$66 and Serial[3]=$2C AND Serial[4]=$17 AND Serial[5]=$00 AND Serial[6]=$00 then nocache
gosub wrong
Goto mainloop

change the value of I to test for optimum performance.