The datasheet for this part repeatedly suggests that it is capable of air gap and contact discharge protection up to ±30kV. However, in section 6.2 ("ESD Ratings") on page 3 of the datasheet (http://www.ti.com/lit/ds/symlink/tpd1e10b06.pdf), it says 30000 V under contact and air discharge ratings. Immediately above that, next to human body model and charged device model, it specifies "±" next to its ratings.
Is this device rated for ±30kV or just positive 30kV air gap and contact discharge protection? Do I have a fundamental misunderstanding of what these ratings mean?