Virtual LAN. A VLAN is a logical interconnection of machines based on an identifying numeric value called the VLAN ID. To segregate the network traffic between different groups of users who share a common communication channel, VLANs can be configured for each group. Although data packets may travel over the same physical medium (like the "air" or over a wired Ethernet network between two locations) they remain separate from the perspective of the user groups who have access to them. VLANs are often used to separate data traffic from voice traffic when computers and wireless (Voice Over IP) phones are present in the same location. The users browse the Internet or transfer files using the default "VLAN 0" that is always present and requires no configuration. The 802.11 Wi-Fi phones are configured to use a different VLAN identifier to send Voice Over IP traffic back to a phone switch on the wired Ethernet.

VSWR (Voltage Standing Wave Ratio) is the ratio of the maximum/minimum values of standing wave pattern along a transmission line to which a load is connected. The connection between two elements of a transmission line (radio-to-cable, cable-to-antenna, etc). is not electrically perfect. As a result, while most of the energy passes through the point of impedance change, some is reflected back. VSWR is a measure of this characteristic. VSWR value ranges from 1 (matched load) to infinity for a short or an open load. For most wireless LAN antennas the maximum acceptable value of VSWR is 2.0. Related values are the Reflection Coefficient and Return Loss which are algorithmically derived from VSWR. VSWR values are measured with a hand-held test meter placed in-line with a transmitter and an antenna. A VSWR measurement of 1.5 or less is considered excellent for WLAN antenna systems. Values greater than 2.0 are considered unacceptable.