User Manual

June 17, 2002 UM0001-1B.00
1-2 User Manual for the CTS Tri-Reader
1.2 Tri-Reader Antenna Type
The Tri-Reader is a loop antenna with a diameter of 75 mm.
1.3 Tri-Reader Interface to Central Processing Unit
There will be a one-to-one (RS422) link between the Tri-Reader and the CPU. They will
operate as a single Remote Ticketing Device.
A shielded RJ45 connector connects the Tri-Reader to the CPU. This link is for the serial
data.
1.4 RF Communication
All RF communication between the Tri-Reader and the CSC will be accomplished at a
carrier frequency of 13.56 MHz according to modulation/demodulation schemes for ISO
14443 Type A, ISO 14443 Type B, and/or GO CARD requirements. At a minimum, the
RF field will be able to power three CSCs in close proximity. The transmitter antenna will
be self-tunable via software resident in the local control processor. The
modulation/demodulation scheme will also be automatically selected by the local
controller.
1.4.1 RF Field Strength
The magnetic field strength is 10 A/m in the center of the antenna and falls off by the third
power of the distance. The electric field strength is determined by the voltage applied to
the coil as well as the efficiency of the antenna as a radiator. The effective applied voltage
is 6 Vrms.
1.4.2 Modulation Types
The signals for communication between the Tri-Reader and the CSC will differ between
card types. In some cases, data will be modulated onto a carrier only, while in others a
subcarrier will also be present. The modulation schemes used for communication also
differ from one card type to another as described below.