DART 200 CDPD Modem User’s Guide | 8 Application Programming |
Device drivers
The DART 200 requires no special device drivers. Serial communications port support provided by the PC Operating System is all that is needed. For modem setup any ASCII terminal emulator, such as Terminal, Hyperterminal, Procomm, Kermit, and so on, is appropriate. For applications use the normal communications port I/O commands supported by the programming language you use.
Application program structure
A CDPD application is similar in general structure to most network based applications. It consists of the following major sections:
DART setup
This is usually done before the DART 200 is put into use, or as a special, first time only function of the application. The needs of the application and the terminal are evaluated based on the protocol being used (TCP, UDP, or SLIP mode) and the appropriate options are chosen. Refer to Chapter 5, DART Supported Protocols, for modem setup samples.
Network connection
Establishing a network connection involves, enabling the Personal Identification Number (PIN) (if used), registering the modem with the network (if not set up to register automatically), then establishing the communication session with a peer device, as follows:
1.If PINs are used, issue the PIN enabling command (AT*E) before attempting to access the network.
2.For application use (as opposed to testing), set up the modem registration as fully automatic, by setting the Registration
This causes the DART 200 to automatically register at power up, and when registration is dropped, for example, due to a power failure or driving out of the coverage area.
3.A session is established for a client by dialing (ATDn command) to establish a logical connection with another device (TCP), or to set up the target device’s IP Address and port for insertion into the data packets to follow (UDP). Refer to the D command in Appendix F, DART AT Command Set, for more information.
Sierra Wireless, Inc. |
