 Frequently Asked Questions
Q: Why should I select Data-Linc's FastLinc IEEE 802.11b WiFi compliant modem for my industrial application?
A: While many IEEE 802.11b WiFi devices claim long-range communication, Data-Linc delivers. What gives the FastLinc family this capability is power-not high power, but optimal power. While the FCC regulates the allowable levels for wireless modems, there is some flexibility in balancing power at the transmitter (wireless modem) with power at the antenna. More power at the transmitter is not necessarily the way to predict that data will get through. Considering the demands of industrial conditions, Data-Linc set the power level of its FastLinc 810E to 200mW, providing the user greater flexibility in selecting types of antennas with a variety of power gains.
Q: We've been using frequency hopping spread spectrum (FHSS) for data transmission. How does direct sequence spread spectrum (DSSS) compare to FHSS?
A: In a high-noise environment, the reliability of the data is dependent on the signal-to-noise ratio. Spread spectrum radio modems typically use one of two spreading methods: direct sequence or frequency hopping.
To deal with noise, direct sequence continuously spreads data across a wide portion of the frequency band. Shifting the center of the spreading code (either done automatically or manually) allows the transmitted data to be moved out of the noisy are of the spectrum.
Frequency hopping, on the other hand, takes incoming data and breaks it down into smaller individual packets, which are then sent on separate frequencies. Once the packets have been transmitted, the data is recompiled in its original format. If a packet cannot be successfully sent on a given frequency, it is resent on another.
Q: I already have a PCMCIA card for my laptop. Why can't I use that?
A: While other 802.11b PCMCIA cards will interface with the FLC810E, the FastLinc 800C Industrial PCMCIA Card offers four to six times the RF output power of most commercially available 802.11b WiFi cards. The high output power (200mW) significantly increases wireless coverage for portable computers roaming within plant facilities where obstructions and interference levels are more severe than office buildings. The FastLinc 800C WiFi performance is further optimized when used with FastLinc 810E modems in 802.11b access point mode. The card will also communicate with existing IEEE 802.11b WiFi compliant networks already in place.
Q: For an in-plant short range application, how do I determine whether the 2.4 GHz SMR or the FastLinc 802.11b is better for my needs?
A: In applications where speed is important and line of site is not a problem, the FLC modems will do the job better than most other 802.11b products. If speed is not important (speed defined as throughput better than 100Kbps) but line of site is marginal or not possible, then the SRM family will perform better then most.
Read more about the Data-Linc FastLinc Family of 802.11b, WiFi short range modems. See also the Data-Linc SRM Family of Smart Spectrum long range, extended temperature modems designed for the most challenging of industrial environments.
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