The industry is currently witnessing the deployment of both IEEE 802.11a technology in the newer 5-GHz UNII band and IEEE 802.11g technology in the 2.45-GHz ISM band. Each standard provides an equivalent 54-Mbps data rate. With dual-band WLAN technology, however, these offerings could be transformed into a universal—albeit more pricey—communications solution. A dual-band network interface card (NIC) can communicate with any access point (AP), ranging from the legacy 1- and 2-Mbps devices deployed in the early days of WLAN technology to the most contemporary 54-Mbps Orthogonal Frequency Division Multiplex (OFDM) devices.
When comparing 2.45- and 5-GHz WLANs, one is confronted with somewhat conflicting claims of superiority. This trend makes it hard for the purchaser of WLAN equipment to separate the hype from real performance. The claims made on the box in that fancy display at the local computer store may not always translate to real performance. For example, claims of operating range are often a good "fish story."
WLAN manufacturers may be conveniently classified into three categories: the 2.45-GHz-only camp, the 5-GHz-only camp (usually startup companies), and those full-service providers offering both frequency bands. Looking at that market breakdown, it becomes clear that dual-band technology offers a really good hedge bet. It is the choice that can most likely communicate with all the above.