> 4.7 | AT+IFC Set Flow Control separately for data directions

> The command AT+IFC can be used to set or query the data flow control on the TA separately for each data direction (send and recive). In contrast to this, flow control settings made with AT\Q are valid in both data directions.
> Please note that AT+IFC and the AT\Q commands are designed for configuring only the TA. The TE must, of course, also be configured. When programming the TE bear in mind that the flow control method set on the TA must be compliant with the flow control method set on the TE. See notes below.
> Syntax

> Test Command AT+IFC=?
> Response(s)
> +IFC: (list of supported <TEflowcontrol>s), (list of supported <TAflowcontrol>s)
> OK

> Read Command AT+IFC?
> Response(s)
> +IFC: <TEflowcontrol>, <TAflowcontrol>
> OK

> Write Command AT+IFC=<TEflowcontrol>, <TAflowcontrol>
> Response(s)
> OK
> ERROR

> Reference(s) |  | PIN |  | ASC0 | ASC1 | USB | MUX1 | MUX2 | MUX3 |  |  | Charge | Q | Last
> V.250 |  | - |  | + | + | - | ± | ± | ± |  |  | - | + | -

> Parameter Description

> <TEflowcontrol>(num)(&W)

> Specifies the method used by the TA when sending data to the TE.
> [0](&F)
> none
> 1
> XON/XOFF
> Local setting on the TA. Terminates flow control in the TA and thus, causes the TA to stop sending data to the remote TA.
> 2
> RTS line
> Local setting on the TA.
> 3
> XON/XOFF
> Used to evaluate flow control in the TA. If the data flow from the TA requires that the transmission be stopped, the TE inserts the XON/OFF control characters into the data stream to be sent, over the air, to the opposite TE. It is the responsibility of the receiving TE to recognize and filter out from the data stream the XON/OFF control characters. So, both TEs must have XON/OFF flow control enabled.
> Also, the receiving TA must be configured to use software flow control. This means, that if the sending TA is configured for AT+IFC=3,x the receiving TA must be set to AT+IFC=y,1. In addition, XON/OFF flow control must be enabled on either TE.
> If the TAs and TEs on both sides are properly configured, the transmission of the XON/OFF control characters will instantly stop the data flow. So, value "3" has an immediate effect on the over-the-air connection between both TEs.

> <TAflowcontrol>(num)(&W)

> Specifies the method used by the TA when receiving data from the TE.
> [0](&F)
> none
> 1
> XON/XOFF
> 2
> CTS line
> Notes

> • | When using XON/XOFF flow control (AT+IFC=1,x or AT+IFC=3,x) in data mode, +++ should not be used while the data transmission is paused with XOFF. Before entering the command mode with +++ the paused transmission should be resumed using the XON character.

> • | For compatibility reasons, the AT+IFC command can be used in Multiplex mode, though the settings will not take effect. However, be aware that whenever you use the AT+IFC write command in Multiplex mode and then save the current configuration to the user profile with AT&W, the changed AT+IFC setting will become active after restart.

> • | The two commands AT+IFC and AT\Q influence each other, i.e. settings made with AT\Q apply to AT+IFC and, vice versa, AT+IFC changes the AT\Q setting.

> • | Bear in mind that when you set a flow control method for one direction on the TA (with AT+IFC) the TE must also be configured accordingly.

> • | The values "1" and "2" have only local effect for the connection between TA and TE. Value "3" has an immediate effect on the over-the-air connection.

> • | XON/OFF flow control is not recommended for transferring binary files. This is because the data stream might contain characters equal to the hex values typically used as XON/OFF control characters, i.e. values 11 (hex) resp. 17 (dec) and 13 (hex) resp. 19 (dec).