Multi-Tech Systems GPRS (MTMMC-G) User Manual

Chapter 12 – V.24 and V.25 Commands  

Multi-Tech Systems, Inc. Wireless GSM/GPRS AT Commands (Document Number S000293I) 

101 

Description:  

This command is controls the operation of local flow control between the DTE and DCE. 

0   none 

(supported) 

1   Xon/Xoff local circuit 103 

(not supported) 

2   RTS 

(supported) 

3   Xon/Xoff global on circuit 103 

(not supported) 

When this parameter is set to 2 (DTE invokes flow control through RTS) DCE 

behaviour is as follows: 

• 

If the DCE has never detected RTS in the high (or ON) condition since startup then it ignores 

RTS as it assumes that this signal is not connected.  

• 

As soon as the DCE detects RTS high the signal acts on it. Therefore subsequent RTS 

transition to OFF will prevent the DCE from sending any further data in both online and 
offline modes.  

• 

This behavior allows the user to use the default settings (hardware flow control) and leave 
RTS disconnected. In the case where RTS is connected and is high at least once, it acts on 
the DCE. 

0   none  

(supported) 

1   Xon/Xoff circuit 104  

(not supported) 

2   CTS  

(supported) 

: When this parameter is set to 0 (none), then CTS is kept high all the time. 

  AT+IFC=<DCE_by_DTE>,<DTE_by_DCE> 

AT+IFC?  
  

+IFC: 2,2 
OK  
Note: Current values 

AT+IFC=?  
 

+IFC: (0,2),(0,2) 
OK  
Note: Possible values  

AT+IFC=0,0    OK  

Note: New values 

 

Description:  

This commands controls the Data Carrier Detect (DCD) signal

.

 

0 

DCD always on 

DCD matches the state of the remote modem’s data carrier

syntax: AT&C <n> 

AT&C0 
Note:  DCD always on 

OK 
Note: Command valid 

AT&C1  
Note:  DCD matches state of the remote 
modem’s data carrier 

OK 
Note: Command valid