1vv0301515 Rev.1
Page 20 of 59
2018-07-18
2.5.4.
Signal Strength & Quality
Assume that the module is registered on a network. The following AT command returns the
received signal strength (<rssi>) and quality (<ber>), giving an indication about the radio link
reliability. The command syntax is:
AT+CSQ
Example 1
The antenna is not connected to the module or network coverage is not present at all.
AT+CSQ
+CSQ: 99,99
OK
The module is in idle state, the antenna is connected, and network coverage is present. Enter
again the previous AT command.
AT+CSQ
+CSQ: 18,99
18 = <rssi> = Received Signal Strength Indication
OK
99 = <ber> the module is in idle state, no Bit Error Rate
AT+CSQ=?
+CSQ: (0-31,99),(0-7,99)
OK
Example 2
Establish a voice call.
ATD 34XY92X4Y9;
OK
voice channel is open
Get the received signal strength (<rssi>) and quality (<ber>) during a voice call
AT+CSQ
+CSQ: 12,0
12 = <rssi> = Received Signal Strength Indication
OK
0 = <ber> = Bit Error Rate in %
Close the voice channel
ATH
OK
Voice Call Establishment
– Originate
Before setting up the voice call, it is assumed that the module is registered on a network and the
signal strength is enough to carry on a reliable radio link.
The following sub-chapters introduce AT commands regarding the audio features of the module.
2.6.1.
Set Module in a Specific Mode
Use the following AT command to set up the module in a specific mode: data, fax class 1, fax
(manufacturer specific), fax class 2.
