Found a couple of typo's. Here is an updated version.
If the code from the multimeter is messed up, you get an output like this:
-018.0 mV DC, AUTO
-018.0 mV DC, AUTO
? 17.2f.3d.40.55.67.7f.8f.9d.a0.b8.c0.c0.e8
-018.0 mV DC, AUTO
-018.0 mV DC, AUTO
In this case, there were two 0xC0's and the 0xD0 was missing.