The Marlock System
The Marlock System uses a key consisting of a piece of metal with holes bored in it, and then
covered up with strips of IR-invisible
plastic. Thus, you can’t see anything in the plastic,
but IR in the keyhole reader can see thru just fine. It decodes this, sends it to a
controller
interface box, which sends it to a controller PC, which says "cool or uncool", and if
cool, then the interface box sends power to
the strike on the door, and turns the LED on the
reader green.
Each area that is to be accessed via Marlock must have some sort of
reader device. This can be either a "keyhole" in the knob, a plate on
the wall with
the keyhole in it, or whatever. The reader is hooked up to a controller interface box. this box is
locked with a really poor
lock (like you’d have on your diskette box) and is located close to
the area being secured, often in the ceiling. The controller interface
box simply provides
power for the reader, the little LED over the top of the reader, and the electric strike locking the
door. The whole
thing is controlled by an IBM PC with a reader keyhole mounted on the front of
the PC which runs to an interface card inside the PC.
To program a key into the system,
one simply inserts it into the keyhole on the front of the PC, and then tells the program when
and
where this key can work. This is stored in its database, and recalled by the reader as
needed. Also the PC keeps logs of when and where a
key was used — whether or not it worked!
There are audit trails all over the place.
If the power goes out, then whether or not
the door opens is dependent upon the strike which was installed. IT can be either fail-safe
(i.e. no power — open!) or fail-secure (i.e. no power- lock!). However, for fire safety code
requirements, companies often install it on the
side of the door which allowed entry to a
restricted area — not exit.
Some of the Marlock cylinders have a small brass spot in
the middle of the LED. This is an emergency override. One would insert a
marlock key, and use
a 9V battery between the key and the pin to provide a signal to the interface controller to pop the
strike. This may
not still be the case however.
Defeating the Marlock System
Since there’s an electric strike all you have to do is provide power to the strike so
it’ll release. This is usually 12-24 volts DC, and is
easily obtained from some lantern
batteries. The activation wires for the strike usually run down inside the door jamb from the
controller interface box. And if you have access to the controller interface box, then just pick the
lock on the front of it. The heavier
wires are for the electric strike (the thin wires are
from the reader). Then just apply power to the thing — use jumper wires to get the
power from
the controller interface box…
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