SCL3711
R
EFERENCE
M
ANUAL
15
3.5.3. Recommendations
The communication between the reader and the user token is sensitive to the presence of
material or objects interfering with the magnetic field generated by the reader.
The presence of conductive materials like metal in the vicinity of the reader and the user token
can severally degrade the communication and even make it impossible. The magnetic field of
the reader generates Eddy or Foucault’s currents in the conductive materials; the field is
literally absorbed by that kind of material.
It is recommended for proper communication to avoid putting SCL3711 in
close proximity of conductive materials.
The presence of multiple user tokens in the field also interferes with the communication. When
several user tokens are in the field of the reader, load of the field increases which implies that
less energy is available for each of them and that the system is detuned. For this reason, SCM
Microsystems has implemented in its driver the support for 1 slot only.
It is recommended to present only one user credential at a time in front of
SCL3711.
The communication between the reader and the user token is sensitive to the geometry of the
system {reader, user token}. Parameters like the geometry and specially the relative size of the
reader and user token antennas directly influence the inductive coupling and therefore the
communication.
SCL3711 was primarily designed and optimized to function with user credentials of various
technologies having the size of a credit card.
It may happen that SCL3711 is not capable of communicating with extremely
large or extremely small antennas.
In order to optimize the coupling between the reader and the user token, it is
recommended to put both antennas as parallel as possible
In order to optimize transaction speed between the reader and the card it is
recommended to place the user token as close as possible to the reader. This
will increase the amount of energy supplied to the user credential which will
then be able to use its microprocessor at higher speeds
