Some of the Questions, All of the Answers
Here are some Frequently Asked Questions about 802.11b, 802.11 WiFi modules, embedded 802.11 module integration, standards and applications. If your specific question isn't answered please use the engineering contact form at the bottom of this page — or call or e-mail a member of our sales team — and we'll answer your inquiry as quickly as we can.
- What version of 802.11 do DPAC's Airborne products support?
- What are the differences between 802.11b and 802.11a and 802.11g technology?
- Can the module operate as a Node or as an Access Point?
- Do I need to purchase a development system to customize the module for my application?
- How much space is available for my custom Web pages?
- What kind of antenna should I use?
- What is the range of your device?
- How do you interface to the Module?
- What drivers do I need to run your device?
- Does the module automatically scan for an Access Point?
- Does the module support an Ad Hoc connection?
- How rugged is your device?
- What is the actual size of the module?
- Do I need to get FCC certification?
- How can I evaluate the operation of your module?
- Where can I get pricing information?
What version of 802.11 is supported?
The Airborne product family fully implements the IEEE 802.11b wireless LAN standard. It works in the 2.4GHz ISM band using Direct Sequence Spread Spectrum radio technology. It is capable of supporting 1, 2, 5.5 and 11Mbps wireless data rates.
back to topWhat are the differences between 802.11b and 802.11a and 802.11g technology?
802.11b Technology was the first WLAN technology to be commercially accepted and widely deployed. 802.11b Operates in the 2.4 GHz ISM band and supports wireless data rates up to 11 Mbps. 802.11b has the largest installed base, is the most mature and cost effective 802.11 technology.
802.11a Technology was developed as a way to increase the wireless data rate. Operating in the 5 GHz ISM band 802.11a supports data rates up to 54 Mbps and provides more channels than 802.11b. However, 802.11a is not backward compatible with 802.11b technology and therefore requires different client and network infrastructure.
802.11g Technology was designed to provide higher throughput with backward compatibility with 802.11b technology. 802.11g Operates in the 2.4 GHz band just like 802.11b and provides wireless data rates up to 54 Mbps. 802.11g Access points can support either 802.11g or 802.11b client radios, so implementation of 802.11g networks requires different network infrastructure, but does not require new client radios. 802.11g Technology is relatively new (as compared to 802.11b) and more expensive.
With data rates up to 11Mbps, compatibility with 802.11b or 802.11g access point and it's technical maturity and lower cost, 802.11b is well suited for a majority of M2M applications.
Can the module operate as a Node or as an Access Point?
The Airborne 802.11b Wireless LAN Module is designed to operate as an 802.11b station device and can operate in an Infrastructure or Ad Hoc mode. In Infrastructure mode the module associates with an Access Point that is connected to a LAN. In Ad Hoc mode the module associates with another station device, such as a PDA, Laptop or another WLN module, in a one-to-one relationship.
Do I need to purchase a development system to customize the module for my application?
No. The Airborne 802.11b Wireless LAN Module has been designed to be a "drop-in" solution that is highly configurable. This means it is self-contained and includes all of the features and functions needed for Wireless LAN connectivity. The comprehensive application interface provides an easy way for an Embedded or LAN application to configure, deploy and operate the module without requiring additional module application programming.
How much space is available for my custom Web pages?
The Airborne 802.11b Wireless LAN Module includes built-in web pages that provide access to the configuration and status. There is space for an additional 15-20 (50-60Kbytes) of custom web pages. Using the Airborne OEM Configuration Tool it is possible to replace the web graphics, integrate modified built-in web pages and add OEM custom web pages.
What kind of antenna should I use?
The Airborne 802.11b Wireless LAN Module provides two U.FL antenna connections, which are designed for operation at 2.4GHz with a 50 ohm impedance. Diversity operation is supported when two antennas are employed. An antenna should be selected with the following criteria in mind:
- Select with the low VSWR ratio,
- Highest gain allowed by the mechanical and price constraints,
- Select for operation at 2.4GHz and 50O impedance,
- Match antenna directionality and radiation pattern to the intended operation - omni-directional or directional,
- Match the antenna polarization, more important for high gain directional antenna
- Minimize inter-connections and number of connectors.
What is the range?
The Airborne 802.11b Wireless LAN Module, operating in the Airborne Evaluation Kit with the supplied antenna, has been observed to reach as far as 1500' (500m). More typically its range is +100' within an office environment and +300' in wider open spaces. Range is very dependent upon the design of the implementation and its deployment. Antenna selection and placement, interference from other RF devices, obstructions such as walls and trees, ambient noise levels, noise levels within the equipment, and the performance of the other communications device such as an Access Point may all have significant impact on the performance of the whole system.
How do you interface to the Airborne 802.11b Wireless LAN Module?
The module provides two ways to communicate with it in an embedded application. One way may use the high-speed serial UART interface, which supports hardware and software handshaking and serial rates from 300bps to 921.6Kbps. The module also supports a slave SPI (Serial Peripheral Interface) port which may be clocked at up to 20MHz. These interfaces are 3.3V TTL compatible and 5V tolerant.
What drivers do I need?
No special drivers are required. Any microcontroller with a serial UART interface can connect with the WLN module and communicate commands, configuration and data with the Airborne 802.11b Wireless LAN Module.
Does the Airborne 802.11b Wireless LAN Module automatically scan for an Access Point?
The module automatically scans for an Access Point with a matching SSID and, as long as the authentication and encryption methods match, the module will associate with the Access Point. The module can also be directed to passively scan for and return a list of detected Access Points.
Does the Airborne 802.11b Wireless LAN Module support an Ad Hoc connection?
The module supports an Ad Hoc or an Infrastructure connection.
How rugged is the Airborne 802.11b Wireless LAN Module?
The module is designed to operate throughout the industrial temperature range, from -40°C to +85°C. It operates from a -40°C cold start and successfully operates all the way to +90°C.
What size is the Airborne 802.11b Wireless LAN Module?
The module's dimensions are: 1.6" x 1.17" x 0.46" (40.6mm x 29.6mm x 11.6mm)
Do I need to get FCC certification?
The Airborne 802.11b Wireless LAN Module is an intentional RF radiator working in the 2.4GHz ISM band, and the FCC requires that equipment that uses the module must be certified. The responsibility for complying with the FCC requirements lies with the manufacturer of the equipment. Other DPAC products have been tested, passed, and have FCC certification. Customers can feel confident that with good design practices, they should have no trouble obtaining FCC certification through compliance testing.
How can I evaluate the operation of the Airborne 802.11b Wireless LAN Module?
Evaluation of the operation of the module is made quick and easy using the Airborne 802.11b Wireless LAN Node Module Evaluation and Development Kit. The kit includes everything required to demonstrate the operation of the module, including an evaluation board with a module and antenna installed, an Access Point, necessary power supplies, evaluation software and thorough documentation.
Where can I get pricing information?
You are invited to call any one of our regional (links to contacts?) sales managers, a representative or call DPAC and ask for an inside sales person.
