Chapter Three
Operation
Man_805U Rev 1.8
Page
17
Chapter Three
OPERATION
3.1
Power-up and Normal Operation
When power is initially connected to the 805U module, the module will perform internal
diagnostics to check its functions. The following table details the status of the indicating
LEDs on the front panel under
normal
operating conditions.
LED Indicator
Condition
Meaning
OK
On
Normal Operation
Radio RX
GREEN flash
RED flash
Radio receiving data
Weak radio signal
Radio TX
Flash
Radio Transmitting
Serial RX
GREEN flash
RED flash
Serial Port Receiving
CTS low
Serial TX
GREEN flash
Serial Port Transmitting
DCD
On
Transparent mode - always on
Controlled mode - on when
communications link is established
DCD
Off
Communications failure or link not
established
Other conditions indicating a fault are described in Chapter Six
Troubleshooting
.
3.2
Serial and Radio Data
The 805U module provides a full-duplex RS232 serial port and half-duplex RS485 serial port
- only one serial port can be used at any one time. The radio communications is half-duplex
- this means that the 805U operates at half duplex. Many applications use full duplex RS232
communications but do not require full duplex - the protocol used operates at half-duplex
and will operate with the 805U without problems. If an application really requires full duplex
communications, then the 805U should not be used.
Data input at the serial port is placed into the input buffer. This buffer will store 2Kbytes of
data, and CTS/RTS control can be configured on the RS232 port to prevent overflow.
