Received Data Flow Control 11-3
Received Data Flow Control Flow control settings are controlled by the AT&Rn and AT&In commands.
The default settings are &R2&I0. Use the following table for more
information about setting the flow control.
For your modem to Command
Pause before sending CTS signal after receiving the
Request to Send (RTS). AT&R0
Ignore the RTS signal.
&R1 is required if your computer or software does not
support RTS
AT&R1
Enable hardware flow control.
The Business Modem sends data to your computer on ly
upon receipt of the RTS signal.
AT&R2
Disable software (XON/XOFF) flow control.
Recommended for non-ARQ (Normal mode) calls (se e
AT&I5). While the Business Modem is online, the only
characters it recognizes are +++, the escape code.
AT&I0 (Default)
Enable software (XON/XOFF) flow control. Use in ARQ
mode only.
Keep in mind that the XON/XOFF characters sent to the
remote computer may interfere with XON/XOFF signaling
between the remote computer and remote device (see
AT&I2).
AT&I1
Force the Business Modem to act on your XON/XOFF
commands, but remove them from the data stream
instead of passing them to the remote computer.
This ensures that the remote computer does not confuse
your XON/XOFF characters with those from its attached
device. This is the recommended setting for ARQ mode.
AT&I2
When using the AT&I2 command, if the call is not in ARQ mode, there is no flow
control on the link. If you send an XOFF to your modem a nd it stops passing data,
it has no way to tell the remote computer and modem to stop sending for a
while, and the local’s buffer may overflow. For more reliable control in non ARQ
mode, see AT&I5.
Enable Hewlett Packard-Host mode. Applies only to
devices attached to an HP mainframe that uses the
ENQ/ACK protocol. Use in ARQ mode only.
If you want to use software flow control to transfer
non-text (binary) files, set serial port and connection rates
equal using &B0 and & N0. See Chapter 9, Controlling
Data Rates for more information about these commands.
AT&I3