3Com 56K Command Reference Manual page 94

11-4 C 11: F
HAPTER LOW
C
ONTROL
For your modem to
Enable Hewlett Packard-Terminal mode. Applies only to
Business Modems attached to terminals in an HP system
that uses the ENQ/ACK protocol. Use in ARQ mode only.
Enable flow control when the connection is not under
error control. For this to work, the remote device must
also have AT&I5 capability. In ARQ mode, a Business
Modem set to AT&I5 operates the same as it does when
set to &I2. It acts on your XON/XOFF commands, but does
not pass them to the remote system. The error-control
protocol enables the devices to control the flow of data
on the phone link.
In non-ARQ mode, a Business Modem set to AT&I5
operates as though flow control were disabled (AT&I0); it
does not look for your typed XON/XOFF commands.
However, it does look for XON/XOFF characters coming in
over the phone link. When the remote device sends
XON/XOFF commands, the Business Modem either
resumes or stops transmitting data over the link and drops
the characters from the data stream.
If both devices are set to AT&I5, operators at each end can
signal the remote device to stop sending. Thus, controlling
the data flow on the phone link and preventing their own
device's buffer from overflowing. At the computer/device
interfaces, the devices independently control the flow of
data through their Transmit Data (AT&H) settings.
Example: Sending
data stream instead of sending them to the remote computer. This will
force the Business Modem to act of the XON/XOFF commands.
will remove XON/XOFF commands from the
AT&I2
Command
AT&I4
AT&I5