Manual
     Smart Machine Smart Decision 
SIM800 Series_AT Command Manual_V1.09  158  2015-08-03 
GSM850_PCS_MODE 
EGSM_PCS_MODE 
ALL_BAND 
Parameter Saving 
Mode 
AUTO_SAVE 
Max Response 
Time 
- 
Reference Note 
  Radio settings are stored in non-volatile memory. 
  The value of parameter <op_band> is different among SIM800 series 
project, please refer to chapter 21 for details. 
6.2.18 AT+CHF Configure Hands Free Operation 
AT+CHF Configure Hands Free Operation 
Response 
+CHF: (list of supported <ind>s),(list of supported <state>s) 
OK 
Test Command 
AT+CHF=? 
Parameters 
See Write Command 
Response 
+CHF: <ind>,<state> 
OK 
Read Command 
AT+CHF? 
Parameters 
See Write Command 
Response 
OK 
ERROR 
If error is related to ME functionality: 
+CME ERROR: <err> 
Unsolicited Result Code 
+CHF: <state> 
Write Command 
AT+CHF=<ind>
[,<state>] 
Parameters 
<ind> 0 Unsolicited result code disabled 
1 Unsolicited result code enabled 
(non-volatile) 
<state>  0 Main audio channel 
1  Aux audio channel 
2 Main audio channel hand free mode 
3 Aux audio channel hand free mode 
4 PCM channel 










