Sierra Wireless DART 200 CDPD Modem manual Slip

DART 200 CDPD Modem User’s Guide 5 DART Supported Protocols

Table 5-4. Host TCP setup (cont.)

AT Command	Req Opt Def Description
AT*K0	D	Use default - Keep-alives not needed at
AT*R0		central site
	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)

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