User guide

Chapter 3 – Supported GSM/WCDMA AT Commands
High Speed HSPA-H4 AT Commands Reference Guide (Document S000483A) 52
+IFC DTE-DCE Local Data Flow Control
Description: This command is controls the operation of local flow control between the DTE and DCE.
Syntax:
Command Responses
Action Command:
AT+IFC=<DCE_by_DTE>,<DTE_by_DCE>
OK
Read Command:
AT+IFC?
+IFC: <DCE_by_DTE>,<DTE_by_DCE>)
OK
Test Command:
AT+IFC=?
+IFC: (list of supported <DCE_by_DTE>s),
(list of supported <DTE_by_DCE>s)
OK
Values: <DCE_by_DTE> Local Flow Control Parameter
0 None
2 RTS. Default
<DTE_by_DCE> Local Flow Control Parameter
0 None
2 CTS. Default
Parameter Storage: The <DCE_by_DTE> and <DTE_by_DCE> parameters are stored in EEPROM using
AT&W.
Examples:
Command Responses
AT+IFC=? +IFC: (0,2),(0,2)
OK
Note: Possible values
AT+IFC=0,0 OK
Note: New values
AT+IFC? +IFC: 0,0
OK
Notes:
If USB port is used:
• The action command is supported for compatibility reasons (but without effect).
• The response to the action command is the same as if sent on UART1 or UART2 and
the value of the both parameters is always 2.
When the <DCE_by_DTE> parameter is set to 2 (DTE prompts flow control through RTS),
the DCE behavior is as follows:
• If the DCE has never detected RTS in the high (or ON) condition since startup, then it
ignores RTS (assuming 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 leaves
RTS disconnected. In the case the RTS is connected and is high at least once, it acts on the
DCE.
When the <DTE_by_DCE> parameter is set to 0 (none), the CTS is kept high all the time.