EG_GenLoc54e_1040_UG_002_UK
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Descriptions and non-contractual illustrations in this document are given as an indication only.
ERCOGENER reserves the right to make any modifications.
Dct_427_02
5.5 Checking the quality of the GSM reception signal
The modem contains the EGM standard library (see the documents
"EG_EGM_CL_xxx_yy" of
ERCOGENER); in this case, the modem will be able to make a call only if the received GSM signal is
powerful enough.
The command
AT+CSQ
allows to know the reception level
(
rssi
) of the signal sent by the closest GSM Base
Transceiver Station (BTS), as well as the reception error code (
g
).
When the SIM card is inserted and the PIN code entered, the command
AT+CSQ
allows to measure the
signal from the BTS of the subscribed operator network.
This command cannot be used without the SIM card.
To check the quality of the GSM signal, do the following operations:
Use a communication software like Hyperterminal, enter the command
AT+CSQ
.
The response is in the following format:
+CSQ : <rssi>, <ber>
with:
<
rssi
>
= indicates the reception level,
<
ber
>
= receive bit error rate.
Check the returned value
<
rssi
>
with the help of the table below.
Table 15 : Value RSSI
Value of
<rssi>
Gain in dbm
Interpretation
Value of
<ber>
Interpretation
0
-113 dbm
Insufficient
0 to 7
See standards ETSI
GSM 05.08
1 to 10
-111 to -95 dbm
Insufficient
11 to 30
-93 to -53 dbm
Sufficient
31 (max)
-51dbm
Perfect
99
Unknown/not detectable 99
Unknown/not detectable
The GSM modem works normally with a minimum
<
rssi
>
between 11 and 15.
Below 10, the signal level is insufficient; the modem cannot work depending on the geographical situation or
the vehicle mobility. Above 15, the signal is sufficient.
For more information about AT commands, see the document "EG_EGM_CL_xxx_yy" of ERCOGENER.
