Bandwidth requirements rarely decrease
The bandwidth demand of tracking embedded system applications only goes in one direction–up–so it’s important to consider the lifetime costs of connection. Choose a modem based on what it may need to do in three to five years, or at least choose one COMe Module that makes upgrades easy.
Automotive special needs
In vehicle-mounted systems, temperature, humidity, and vibration can be extreme. AEC-Q100 qualified devices manufactured in ISO/TS 16949 certified sites will ensure reliable, long-life operation. Qualification on-board computer tests for each industrial computer component should conform to ISO16750, Road vehicles – Environmental conditions and testing for electrical and electronic equipment. This applies to on-board computer and industrial devices that operate in demanding environments, such as ships or railcars.
Emergency call systems are growing in popularity
Increasingly, cars are fitted with systems that automatically report accidents or aid recovery after theft. The U.S., Europe, Russia, and Brazil have established initiatives to support such embedded systems and that will increasingly be required by government mandate. For these applications (see the example in Figure 3), an “in-band modem” is often needed. It sends data over the modem voice channel in a similar way to a fax machine sending data over the telephone lines. It’s needed because operators prioritize voice over data in mobile networks. In the event of an accident, the voice industrial computer channel becomes the crucial link for transmitting data to emergency services. Check that the proposed solution supports in-band modems on both 2G and 3G networks.
refer to:
http://embedded-computing.com/articles/the-fast-growing-m2m-market-presents-a-series-of-wireless-design-challenges/