9
GSM: wireless network status LED -
red
The numbers of the GSM LED flashing sequence signs the current RSSI signal strength of the
wireless network (more flashes are meaning a better signal reception).
There is 10 seconds between the flash signals. One flashing takes 50 msec, then half a second
breaking continues.
RSSI value
(AT+CSQ)
Cellular signal strength
(receive)
GSM LED flashing
99
unknown, faulty value
0 - Bad
0..7
-113 dBm.. -99 dBm
1 - Weak
8…11
-97… -91 dBm
2 - Average
12..15
-89… -83 dBm
3 - Average
16…19
-81… -75 dBm
4 - Good
20…23
-73… -67 dBm
5 - Good
24…27
-65… -59 dBm
6 – Perfect
28…31
-57… -51 dBm
7 - Perfect
STA: Status LED -
yellow
The STA LED assures information about the current operation. It will be active only if the
wireless signal transmission permitted. In this case from the beginning of the signal transmission
the LED starts to flashing.
It has 3 modes:
lighting continuously: the last wireless signalling was succesful
with 3 second of breaks * nr. of flashing (the light interval period is half a seconds),
failure code (see later)
Turned off: wireless operation mode, no error
ALR
-
Inactive
-
-
PWR
Operation
Signs the presence of the processor power
supply (3,3V)
green
lights
