The Duprex dual, supervised reader extender (RF) from Cypress Computer Systems of Lapeer, Mich., extends the distance between any two access control readers and a controller. The unit can span up to 10,000 ft. and features alarm output from the central unit, which indicates power or communication loss with the reader at the remote unit. The Duprex RF is available in a wired version, as well as short- and mid-range wireless, fiber optic, Ethernet and single reader models.