Specifications
SIM900 AT Command Manual       
SIM900_AT Command Manual_V1.03  34  12/24/2010 
2.2.29 AT&D Set DTR Function Mode 
AT&D Set DTR Function Mode 
Response 
This parameter determines how the TA responds when circuit 108/2 (DTR) 
is changed from the ON to the OFF condition during data mode. 
OK 
ERROR 
Execution 
Command 
AT&D[<value>] 
Parameter 
<value> 0 TA ignores status on DTR. 
1 ON->OFF on DTR: Change to Command mode with 
remaining the connected call. 
2 ON->OFF on DTR: Disconnect call, change to Command 
mode. During state DTR = OFF is auto-answer off. 
Reference 
V.25ter 
Note 
2.2.30 AT&F Factory Defined Configuration 
AT&F Factory Defined Configuration 
Response 
TA sets all current parameters to the manufacturer defined profile. 
OK 
Execution 
Command 
AT&F[<value>] 
Parameter 
<value> 0  Set all TA parameters to manufacturer defaults. 
Reference 
V.25ter 
Note 
Parameter impacted by &F command: 
Command  Parameter name  Default value 
ATE  <echo>  0x01 
ATQ  <result>  0x00 
ATV  <format>  0x01 
ATX  <result>  0x04 
AT+IFC  <TA_by_TE>  0x00 
AT+IFC  <TE_by_TA>  0x00 
ATS0  <num>  0x00 
ATS3  <char>  0x0D 
ATS4  <char>  0x0A 
ATS5  <char>  0x08 










