Multi-Tech Systems GPRS (MTSMC-G) ユーザーズマニュアル

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Chapter 5 – Call Control Commands 
Multi-Tech Systems, Inc. Wireless GSM/GPRS AT Commands (Document Number S000293I) 
21 
 
 
Answer a Call   A 
Description: 
When the product receives a call, it sets the 
RingInd signal and sends the ASCII “RING” or “+CRING: 
<type>” string to the application (+CRING if the cellular result code +CRC is enabled). Then it waits for 
the application to accept the call with the ATA command. 
Values: 
No parameters. 
Syntax:   ATA 
Command 
Possible responses
 
 
RING 
Note: Incoming call  
ATA 
Note: Answer to this incoming call  
OK  
Note: Call accepted 
ATH 
Note: Disconnect call  
OK  
Note: Call disconnected 
 
 
Remote Disconnection 
This message is used by the product to inform the application that an active call has been released by the remote user. 
The product sends “
NO CARRIER” to the application and sets the DCD signal. 
In addition, for AOC, the product can release the call if credit has expired (release cause 68 with +CEER command). 
 
 
Extended Error Report   +CEER 
Description
This command gives the cause of call release when the last call set up (originating or answering) failed. 
Values:  
No parameters 
Syntax:   
AT+CEER 
Command 
Possible responses
ATD123456789; 
Note: Outgoing voice call 
NO CARRIER 
Note: Call setup failure  
AT+CEER 
 
Note: Ask for reason of release  
+CEER: Error <xxx> 
OK 
Note: <xxx>is the cause information element values 
from GSM recommendation 04.08 or specific  Call 
accepted 
Note:  “NO CARRIER” indicates that the AT+CEER information is available for failure diagnosis. 
 
 
DTMF Signals   +VTD, +VTS 
+VTD 
Description: 
The product enables the user application to send DTMF tones over the GSM network. This command is 
used to define tone duration (the default value is 70 ms 
± 5 ms according to 3GPP 23.014).  
Values:  
<n>  tone duration.  
This refers to an integer <n> that defines the length of tones emitted as a result of the +VTS 
command. This does not affect the D command.  
A value different than zero causes a tone of duration <n> *100 milliseconds. 
A value of zero (default value) causes a tone duration of 70 ms 
± 5 ms. 
Note: The value is used modulo 256.