Specifications
SIM900 AT Command Manual       
SIM900_AT Command Manual_V1.03  79  12/24/2010 
OK 
If error is related to ME functionality: 
+CME ERROR: <err> 
Execution Command returns received signal strength indication <rssi> 
and channel bit error rate <ber> from the ME. Test Command returns 
values supported by the TA. 
Parameters 
<rssi> 
0   -115 dBm or less 
1   -111 dBm 
2...30   -110... -54 dBm 
31  -52 dBm or greater 
99  not known or not detectable 
<ber> (in percent): 
0...7  As RXQUAL values in the table in GSM 05.08 [20] 
subclause 7.2.4 
99 Not known or not detectable 
Reference 
GSM 07.07 [13] 
Note 
3.2.36 AT+FCLASS FAX: Select, Read or Test Service Class 
AT+FCLASS FAX: Select, Read or Test Service Class 
Response 
+FCLASS: (list of supported <class>s) 
OK 
Test Command 
AT+FCLASS=? 
Parameter 
See Write Command 
Response 
+FCLASS: <class> 
OK 
Read Command 
AT+FCLASS? 
Parameter 
See Write Command 
Response 
TA sets a particular mode of operation (data fax). This causes the TA to 
process information in a manner suitable for that type of information 
OK 
Write Command 
AT+FCLASS= 
<class> 
Parameter 
<n> 0 data 










