Specifications
SIM900 AT Command Manual       
SIM900_AT Command Manual_V1.03  18  12/24/2010 
Execution 
Command 
ATA 
Response 
TA sends off-hook to the remote station. 
Note1: Any additional commands on the same Command line are ignored. 
Note2: This Command may be aborted generally by receiving a character 
during execution. The aborting is not possible during some states of 
connection establishment such as handshaking. 
Response in case of data call, if successfully connected 
CONNECT<text> TA switches to data mode. 
Note:  <text> output only if ATX<value> parameter setting with the 
<value>>0 
When TA returns to Command mode after call release 
OK 
Response in case of voice call, if successfully connected 
OK 
Response if no connection 
NO CARRIER 
Reference 
V.25ter 
Note 
See also ATX 
2.2.3 ATD Mobile Originated Call to Dial A Number 
ATD Mobile Originated Call to Dial A Number 
Execution 
Command 
ATD<n>[<mgsm
][;] 
Response 
This Command can be used to set up outgoing voice, data or fax calls. It 
also serves to control supplementary services. 
Note: This Command may be aborted generally by receiving an ATH 
Command or a character during execution. The aborting is not possible 
during some states of connection establishment such as handshaking. 
If no dial tone and (parameter setting ATX2 or ATX4) 
NO DIALTONE 
If busy and (parameter setting ATX3 or ATX4) 
BUSY 
If a connection cannot be established 
NO CARRIER 
If the remote station does not answer 
NO ANSWER 










