High-data throughput technologies, such as, Ethernet, WiFi and Bluetooth have become quite popular in business and industrial environments. These technologies allow designers to leverage existing infrastructures (via base stations and access points), utilize high-bandwidth flexibility in transmission schemes, and provide adequate networking within RS-232 systems up to 300 feet of range.
On the downside, added cost and complexities can arise in the Ethernet-to-serial conversions needed for these technologies.
As an alternative, proprietary wireless RS-232 systems that specialize in long range and low data throughput can be very cost effective while providing the following benefits to an RS-232 system:
Whether designing wireless data communication into new or legacy systems, designers can benefit from minimal to no configuration or programming requirements needed for the wireless RS-232 link. Where configuration is needed, standard modem AT or binary commands are usually available to the designer. Many manufacturers of wireless transceiver modules take into account the varying needs of OEMs and have designed-in simple interfaces to their transceivers.
Wireless transceiver modules often support addressing and networking configuration needed for common point-to-point and point-to-multipoint topologies. The easiest to use and integrate modules go one step further by offering completely transparent communication between devices. Transparent wireless RS-232 communication appears as wired communication to the system as the wireless link passes data in the same form as is was received. Where transparent communication is not available, transceiver manufacturers try to minimize the software requirements needed outside of the wireless link to pass the system's data.
Across all networking topologies wireless brings the obvious benefit of extended range.
Depending on the wireless transceiver modules, the range of RS-232 communication can be extended up to 20 miles or more in pure line-of-sight conditions. More typically, designers can expect two to seven miles in line-of-sight conditions and 300 feet to ¼ mile in urban or industrial environments. In long-range applications, wireless communication links offset the expenses and challenges inherent in running long cables. When the range of a system fluctuates, as in mobile or remote applications, the wireless benefit of portability becomes valuable to the designer.
The implementation of mobile RS-232 systems becomes more simplified when using wireless RS-232 technologies. Handheld devices, radio frequency identification (RFID) devices, vehicle applications and other mobile designs can be moved to various distances and locations using wireless RS-232 while maintaining reliable communication links.
Designers are asking that equipment be easier and quicker to install. Wireless RS-232 links can be up and running in a fraction of the time it takes to deploy a wired link, especially when working with long range or legacy systems. Removing the expensive hardware and labor costs associated with wired installations also makes wireless solutions more affordable. Where transparent communication is available, introducing a wireless link can be as simple as a plug-and-communicate scenario. The ease of installation also makes wireless transceiver modules available to an increasing number of product designs.
Leveraging existing intellectual property and products by adding wireless RS-232 compatibility to legacy systems is a key benefit realized by OEMs wanting to extend their products' capabilities and market reach. Designers find wireless solutions as an effective means for extending product lines without drastically redesigning existing products and systems. When standalone radio modems are used as the wireless link, existing products and systems require no redesign and can be deployed immediately.
As an example, Digi has a line of wireless transceiver modules that meet many of the performance and ease of use suggestions discussed. Their modules are all drop-in wireless RS-232/485 solutions that are FCC and other agency approved for use throughout the world. Integrating these wireless data communication solutions is as simple as sending serial data from a microcontroller or comm port, while the Digi module handles all of the complexities of spread spectrum transmission and reception. Of particular note is their ability to communicate at short or long range while consuming low power and maintaining high levels of interference rejection over transparent peer-to-peer, point-to-point, point-to-multipoint and multi-drop networks.
The Digi 9XStream 900 MHz Wireless OEM Module is a frequency-hopping spread spectrum transceiver that uses a simple UART interface to communicate with the host system. It has transmission power output of 140 mW and operates at long ranges (up to ¼ mile in urban environments and up to 20 miles in line-of-sight conditions) due to its excellent receiver sensitivity of –110 dBm. Additionally, the 9XStream uses proprietary filtering technology to provide interference immunity, including 70 dB of cell phone and pager rejection (10 million times attenuation). providing OEMs with a robust, reliable wireless method to transmit serial data.