Installation guide

Access Control by Example Materials Planning | en 7
Bosch Security Systems Introductory Guide | 1.0 | 2009.10
2.2.1 Card reader technologies
Card readers differ in two important respects: scan frequency and protocol.
Scan Frequency: 125kHz vs. 13.56MHz
The most common scan frequencies for readers are 125kHz and 13.56 MHz.
125kHz is proven technology prevalent in the USA and in Eastern Europe. The cards and
readers tend to be lower priced.
13.56 MHz is newer, more secure technology prevalent in EMEA and increasingly in APAC
countries. Hardware is currently priced somewhat higher.
RS-485 vs Wiegand:
Decide early whether to use Wiegand or RS-485 technology for the readers; each has its own
advantages and disadvantages. Maximum cable length and wiring topology are different, as
the following table shows.
2.2.2 Credentials technology
Decide on the credentials technology you wish to use. For Wiegand readers the choice
includes e.g. iCLASS (3.56MHz) and EM (125kHz) cards. For RS-485 readers there is a wide
choice: MIFARE, HITEC or LEGIC. These credentials types are available in different physical
formats: Most common are the classic credit-card sized identity cards, and the smaller tokens
4. Office Card reader
Electric door opener
REX by motion detector
Magnetic contact
Note:This secured room, which already houses the
computer, is the obvious place to put the access
controller itself.
5. Treatment room Nothing
Room Access control hardware
RS-485 Readers Wiegand Readers
Wiring topology bus, (“chain”) star
Maximum cable length 1200m 100m
Number of wires needed
for the reader
4 10
(The slightly lower cost of
Wiegand readers is offset by
higher wiring costs and
potential for wiring errors).