Sierra Wireless DART 200 CDPD Modem - Manual (Page 76)

DART 200 CDPD Modem User’s Guide 5 DART Supported Protocols
Sierra Wireless, Inc. 5-22
Table 5-4. Host TCP setup (cont.)
AT Command Req Opt Def Description
AT*K0 D Use default - Keep-alives not needed at
central site
AT*R0 D Use default - Does not apply to TCP
AT*T0 D Use default - Does not apply to TCP
SLIP
Serial Line Interface Protocol (SLIP) is the defacto standard for
encapsulating TCP/IP protocol over dedicated and/or switched serial
lines. It is a useful and reliable way to allow mixes of hosts and routers to
communicate with one another in various combinations.
Most casual end-users do not encounter SLIP in the above form. Instead,
they find SLIP being used with TCP/IP stacks (usually referred to simply
as stacks) in a variety of PC programs designed to provide support for
multiple TCP or UDP applications over networks of various types (X.25,
LANs, satellite, and so on) including the Internet. CDPD is another such
network.
These stacks frequently include additional functions such as electronic
mail, various forms of telnet, ping, Internet browsers, and file
downloading using File Transfer Protocol (FTP). In addition, most of
these programs provide a multitasking end-user application programming
interface (API) to the stack (usually, Winsock), for developing custom
communications applications. These programs are also used with PCs
attached to the CDPD network.
The DART 200 provides SLIP capability. When operating in SLIP mode,
the modem’s internal TCP/IP stack is bypassed (but not its CDPD stack)
and, the modem acts as a router passing data between the software
package’s stack, and the network, such as the Internet or a private
network using Internet Protocol, attached server applications.
Using such a package allows the design of applications that need
multiple communications sessions active concurrently. For example, a
public safety application where a police car has active sessions
simultaneously with the NCIC in Washington, the State Bureau of Motor
Vehicles, and the local police system.
Modem setup for SLIP
In SLIP mode, the following profile parameters are not operational and
can be ignored. Their function is provided by the PC-based software
package.
• Data forwarding operation (\Fn)
• Select Server Mode (*An)
• Manual Transmit Control (\Mn)