New wireless serial device server uses standard 802.11b WiFi to connect RS232 serial ports to a PC or network in a flexible, secure and low cost way.
Much equipment still has a RS232 serial port as the main data transfer method. Even new equipment can have serial ports because they are easy and cheap to implement, most microcontrollers support them efficiently and designers know how to use them. Also, data can be transferred reasonably fast at 115Kbps, which is sufficient for most purposes.
The type of equipment involved includes shop tills, bar code scanners, weighing scales, sensors, medical instruments, industrial machines and other systems that need control information or collect data. These all need to communicate with PCs and PC networks and the standard serial connection has commonly been replaced by Serial to Ethernet converters, also known as Serial Device Servers, for a long time.
Now though, an 802.11 wireless Serial Device Server is available as well. This new product allows existing serial port equipment to be connected to a network using wireless rather than network cables. This obviously has benefits in reduced cabling needs, more freedom for equipment location and speed of installation but could give problems of expense and security vulnerability. However, these new wireless servers are low cost while incorporating the latest 128-bit WEP (Wireless Equivalent Privacy) to ensure that communications remain safe.
Additionally, they can be configured to work in different modes to suit the application. If a single point to point communication is all that is needed, then the units can be set in Ad-hoc mode and function as a wireless serial lead. But, if multiple connections are required or a wireless network already exists, then they can be configured in infrastructure mode so that they can link through any standard wireless access point.
From the designer's point of view, these units could not be simpler to use as they include support for many different protocols. This means that it is easy to select the exact type of communication needed, either as a network by IP address or as a Virtual Serial Port to reuse existing software.
As they use the standard 802.11 WiFi protocol, these units can communicate with existing wireless networks or to low cost WiFi cards, which also keeps the money-men happy.
Kanda are manufacturers and distributors of tools for electronic engineers and trainers. Products include microcontroller and PLD training kits, programmers, cables and embedded modules. PC interfaces for CAN Bus, Bluetooth, USB and ZigBee wireless.
Issued by: Kanda on 05 September 2005.
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