Emprex 8X DDS - Manual (Page 12)

8X DDS DVD± R/RW Drive
8
About This Dual Digital Storage Drive
This drive is also a RPC2 DVD-ROM drive and according to DVD-Forum,
PC chip must be designed into DVD-ROM drives to record how many times
a user has changed the region code. The first region code will depend on
the DVD title you play and you are allowed to modify the region code 5
times
(including the initial one). After the fifth alteration, the region code will
be locked and only those DVD titles of the same region code could be
played afterwards, so set the code carefully.