Installation guide

Access Control by Example Glossary | en 29
Bosch Security Systems Introductory Guide | 1.0 | 2009.10
Mode wet/dry An AMC connection is in “wet mode” when the AMC provides a voltage to the peripheral
device via that connection. “Dry mode” is the opposite, i.e. no voltage is provided via the
connection. The mode is determined by a jumper setting inside the AMC unit. It is important
that devices with their own power supplies be connected only in dry mode.
P
Protective diode A small component wired in parallel with a magnetic component in order to dissipate any
harmful excess voltage induced by powering off the magnet.
R
REX A Request to EXit device. An electronic device, typically a push button or a motion detector,
which signals the need to unlock a door to allow exit.
RS-485 A digital communications standard which is especially effective over long distances and in
electrically “noisy” environments. Here it is an alternative communication medium to Wiegand
for connecting readers to access controlers. RS-485 uses a bus topology and has a longer
range than Wiegand.
T
Tier An access control system can be considered as consisting of three tiers: the electrical
components (low tier), the access controllers (middle tier) and the software host system
(high tier).
Time model A structure of hours of the day which is defined by administrators as a named entity in an
access control system. System administrators can control, for instance, the opening times of a
door, or the valid attendance times of a person based on such time models, thus accelerating
the software configuration process.
W
Wiegand The Wiegand interface is a common wiring standard for card readers