= Solution
In <differential Manchester encoding>, every data <bit> still has a compulsory transition at its midpoint for <clock recovery>. The data value is specified by whether a transition occurs at the beginning of the <bit>, rather than by the direction of the midpoint transition. One convention is beginning transition for zero and no beginning transition for one; interchanging the meanings consistently also works.
Reversing the signal polarity exchanges high and low everywhere, but preserves both the presence and the absence of transitions. A receiver using <differential Manchester encoding> therefore decodes the same data after a polarity reversal, provided it has acquired the timing and boundary reference. Ordinary <Manchester encoding> with a fixed low–high/high–low interpretation would exchange the two data values. The advantage is
$$
\boxed{\text{self-clocking transmission insensitive to a global polarity reversal}.}
$$
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