Wi-Fi Glossary for Site Inspections

Access point
A wireless access point (WAP) is a device that allows users to connect to a wired digital network.

ADSL (asymmetric digital subscriber line) is called asymmetric because most of its bandwidth is devoted in the downstream direction. Applications require high-speed internet download bandwidth, while user requests and responses are small and require little bandwidth. ADSL runs anywhere from 608Kbps to 1.5Mbps downstream and 128Kbps to 384Kbps upstream. 

Cable lines run through a cable modem at speeds between 500 Kbps and 1 Mbps for downloads, and between 128 Kbps and 500 Kbps for uploads.

DSL (digital subscriber line) is an advanced broadband Internet access method that uses copper telephone lines to carry high-speed bandwidth for an always-on Internet connection. 

An IDSL (individual digital subscriber line) provides DSL technology over an ISDN (integrated services digital network) circuit, an international communications standard for sending voice, video, and data over digital telephone lines or normal telephone wires. ISDN supports data transfer rates of 64 Kbps (64,000 bits per second). IDSL uses an ISDN circuit and runs at the same speed as ISDN but has an always-on Internet connection. 

A router is a small device that transfers data between computer networks. A router is connected to two or more data lines from different networks.

Satellite Internet uses geo-stationary satellites that orbit above the equator. Broadband technologies and IP-spoofing techniques allow the satellites to be used for high-speed Internet access. A point-to-point satellite network provides a dedicated link between two sites that are located within the same satellite range.

SDSL (symmetric digital subscriber line) connections use a single twisted-pair line carrying 1.544Mbps in each direction. The line is called "symmetric" because the data load is the same in both directions, downstream and upstream. 

A T1 line is made up of 24 digital channels. A full T1 connection should accommodate from one to over 200 users and other services from an Internet service provider (ISP). T1 lines transmit at 1.544 Megabits per second.

T3 lines consist of 21 T1 lines combined together to form a circuit. This T3 circuit is capable of 44.736Mbps both upstream and downstream. 

Trunking/Trunk service
Trunking allows an Internet connection to provide network access to many clients by sharing a set of lines or frequencies rather than providing them individually to each user. A trunk is a channel between two points, with each point being either the switching center or the node.

WiMAX (worldwide interoperability for microwave access) is a fourth generation (4G) wireless communications standard designed to provide 30 to 40 Mbps upload and download speeds. WiMax offers data-transfer speeds that can be superior to conventional cable-modem and DSL connections, but bandwidth is often split between multiple users.