GFU27 User Guide
Version
3.0
12
2.2
LED indicators
SYMBOL
LED NAME
COLOR
DESCRIPTION
!
Mode
Red
Active if modem switched to Programming mode
Rx/Tx Green
Active if modem receives or transmits data over the
serial interface (min. light on 200 ms)
Link Red
Active whenever an identifiable data message exists
on the radio channel. (min. light on 200 ms)
Power
Green
Active if Power connected to modem
Figure 2.2 Led indicators
2.3
RF interface
The GFU27 has a single TNC female connector with impedance of 50 Ohm.
The frequency band of the modem is tuned at the factory. The user can change the operating
frequency of the radio modem afterwards within the tuning range of 70 MHz. Of course, all
local regulations set forth by the authorities must be taken into consideration.
The radio channel spacing is set at the factory and can also be changed afterwards by the user
in between 12.5, 20 and 25 kHz. The data speed depends on the chosen radio channel
spacing. A channel spacing of 25 kHz enables a data speed of 19200 bps and channel spacing
of 12.5 or 20 kHz enables, correspondingly, a data speed of 9600 bps. The data speed of the
radio interface is irrespective of the data speed of the serial interface.
