3Com 56K Command Reference Manual page 155

Command Function
&H1
&H2
&H3
&In Received data software flow (XON/OFF) control.
&I0
&I1
&I2
&I3
&I4
&I5
&Kn Enable or disable data compression.
&K0
&K1
&K2
Ampersand (&) Command Set
Use hardware flow control. Requires that your
computer and software support Clear to Send
(CTS) at the EIA-232 interface.
Use software flow control. Requires that your
software support XON/XOFF signaling.
Use both hardware and software flow control. If
you are unsure about what your equipment
supports, select this option.
Disables XON/XOFF flow control of received data.
The modem acts on your typed XON/XOFF
commands, Ctrl-S or Ctrl-Q, and passes them to
the remote device.
The modem acts on your XON/XOFF commands,
but removes them from the data stream instead
of passing them to the remote device. This is the
recommended setting for ARQ mode.
Hewlett Packard-Host mode. Applies only to
modems attached to an HP mainframe that uses
the ENQ/ACK protocol. Use in ARQ mode only.
Hewlett Packard-Terminal mode. Applies only to
modems attached to terminals in an HP system
that uses the ENQ/ACK protocol. Use in ARQ
mode only.
This setting is designed to enable flow control on
the phone link when the connection is not under
error control. For this to work, the remote device
must have &I5 capability.
Disable data compression.
Use auto-enable/disable. The modem enables
compression if the serial port rate is fixed (&B1)
and disables compression if the serial port rate
follows the connection rate (&B0) because
compression offers no throughput advantage
when the serial port and connection rates are
equal; in fact, compression may degrade
throughput.
Always enable data compression.
B-7