
FASTRAK MANUAL
Rev. G
27
JUNE 2012
8. System Operation
8.1 I/O Considerations
Currently, there are two possible interface configuration options available on the FASTRAK
system; the standard RS-232 serial configuration or the optional RS-422 configuration. Each
configuration supports either Binary or ASCII formats.
RS-232
The RS-232 is the most commonly used port both in binary and ASCII formats
because of its commonality and the fact that it supports high baud rates. The RS-232 port should
be used where host to FASTRAK physical separation distances are no greater than 50 feet and
baud rates can be kept low. (Higher baud rates will require shorter cable lengths for reliable
operation.)
Ensure that your RS-232 cable connects the
FASTRAK TRANSMIT
data pin
(pin 3) to the
HOST’S RECEIVE
data pin and that the
FASTRAK RECEIVE
data pin (pin 2) is connected
to the
HOST’S TRANSMIT
data pin. Also ensure that the RS-232 cable connects the
FASTRAK GROUND
(pin 5) to the
HOST’S GROUND
pin. Note that the host computer’s
ground pin may be designated as “Signal Ground” or some other comparable phrase.
RS-232 Cable Connections
FASTRAK
HOST
Transmit (pin 3) ----------------------------------------- Receive
Receive (pin 2) ------------------------------------------------- Transmit
Ground (pin 5) ------------------------------------------ Ground
RS-422
The optional RS-422 port is used where large separation distances between the
FASTRAK and the host are anticipated. If high baud rate operation over a long communication
cable is required but the host computer does not have an RS-422, inexpensive RS-422/RS-232
conversion modules are available commercially. Please contact Polhemus Customer Service (see
Contacting Polhemus Customer Service
) should you need suggestions on where to
locate these modules.
As with the RS-232 port, the RS-422 transmit signals from the FASTRAK must be connected to
the Host’s Receive signals and the FASTRAK’s Receive signals must be connected to the Host’s
Transmit signals. Signal polarity conventions must be strictly observed. See diagram below for
connections.
RS-422 Cable Connections
FASTRAK
HOST
RxB; receive high (pin 1) ----------------- TxB; transmit high
TxB; transmit high (pin 4) ----------------- RxB; receive high
RxA; receive low (pin 6) ----------------- TxA; transmit low
TxA; transmit low (pin 9) ----------------- RxA; receive low
8.2 Powering Up FASTRAK
To power-up your FASTRAK system, first ensure that the power switch on the back panel of the
FASTRAK is in the “off” position and the power supply brick is not plugged into the AC wall