Sierra Wireless DART 200 CDPD Modem Initiate Slip Serial Line IP Mode Session, Telnet Keep- Alive

DART 200 CDPD Modem User’s Guide F DART AT Command Set

Table F-4. Commands beginning with asterisk (*) (cont.)

*S	Initiate SLIP (Serial Line IP Mode) Session
	Initiates a SLIP session on the serial port. It is also used to return to SLIP mode following an escape.
	SLIP mode can be escaped by using the escape sequence or by causing an active to inactive transition
	of the DTR lead with &D1 or &D2 specified.
	Format:
	AT*S	Enable SLIP mode
	Result codes:
	OK	Command complete
	DETECTED ILLEGAL	MAS or SLIP address is missing
	NEI
*T	Telnet Keep- Alive
	Provides a facility to allow modems supporting telnet applications to time out, or keep-alive a telnet
	session with no current activity.
	This facility can work in transmit only mode, receive only mode, or in both modes. It uses the non-
	intrusive telnet NOP command packet and a keep-alive time-out (S-Register 86) to implement the
	function. The timer is restarted whenever any data is sent or received. The default time-out value is 120
	minutes.
	If the timer expires in transmit or transmit/receive mode pending data or the telnet NOP command is
	forwarded. For a half open connection this transmission eventually causes the connection to be closed
	because the other end is not able to acknowledge receipt of the data packet.
	If the timer expires in receive or transmit/receive mode the modem switches to command mode and
	issues an ATH command to close the connection. While in receive mode incoming keep-alive packets
	(the telnet NOP) is automatically discarded by the telnet protocol.
	For one way keep-alives (transmit only at one end and receive only at the other) set the transmit time-
	out value to be less than the receive time-out value to ensure proper operation. For keep-alives in both
	directions (transmit/receive) set the time-out values at each end as equal.
	The keep-alive algorithm has a small amount of hysteresis built in to cause the transmit time-out to
	occur ahead of the receive time-out in order to maintain the link. If there is not a DART on the remote
	end of a session using the keep-alive function then the application at the remote end must handle keep-
	alive generation and/or discarding.
	Format:
	AT*T0	No keep-alives (default)
	AT*T1	Transmit only
	AT*T2	Receive (and discard) only
	AT*T3	Transmit/receive
	Result codes:
	OK	Valid argument
	ERROR	Invalid argument

PN1197-00 Revision 1.0 F-23