Access control can come in many forms
from fingerprint or retina recognition to
simple door intercom systems

Biometrics such as
the fingerprint
remain at the
security concious
end of the market,
however with prices falling as the technology becomes more widespread, these systems are becoming more of a common sight.
The most popular readers are
card swipe, similar to when your
credit card is read when shopping.
A more versatile system is the prox
reader which requires no contact at all