This report from the European Commission supported Widebeam project provides an exhaustive guide to electronic communications within and between small to medium businesses.
http://www.isomatic.co.uk/
Cable installation company providing communications cables for voice and data installations.
http://www.tkmcommunications.com/
A source for information on videoconferencing standards and other communications standards related to videoconferencing.
http://standards.pictel.com
Telco line (ex. T1, DSL, ISDN) price calculator and service locator.
http://www.telcoexchange.com
Aptly named, this source includes extensive information on WAN/LAN data and telecommunications protocols.
http://www.protocols.com
Includes current technology news articles, and guides for topic areas such as infrastructure, e-Commerce, WAN systems and telephony, and messaging and collaboration.
http://www.networkcomputing.com/
Network cabling basics, with tutorials on Ethernet, Token Ring, Fibre, and installation practices.
http://www.datacottage.com/
Information on the IETF's Multiprotocol Label Switching Standard.
http://www.mplsrc.com/
Provides IT professionals with a place to locate information on key technologies.
http://www.itprc.com/
This is a set of technical resources for network engineers and system administrators; includes whois and traceroute.
http://www.geektools.com/