3Com 56K Use hardware flow control. Requires that your, CTS at the EIA-232 interface, Mode only

Ampersand (&) Command Set B-7

Command	Function
	&H1	Use hardware flow control. Requires that your
		computer and software support Clear to Send
		(CTS) at the EIA-232 interface.
	&H2	Use software flow control. Requires that your
		software support XON/XOFF signaling.
	&H3	Use both hardware and software flow control. If
		you are unsure about what your equipment
		supports, select this option.
&In	Received data software flow (XON/OFF) control.
	&I0	Disables XON/XOFF flow control of received data.
	&I1	The modem acts on your typed XON/XOFF
		commands, Ctrl-S or Ctrl-Q, and passes them to
		the remote device.
	&I2	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.
	&I3	Hewlett Packard-Host mode. Applies only to
		modems attached to an HP mainframe that uses
		the ENQ/ACK protocol. Use in ARQ mode only.
	&I4	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.
	&I5	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.
&Kn	Enable or disable data compression.
	&K0	Disable data compression.
	&K1	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.
	&K2	Always enable data compression.