Chapter 2. Telephone Systems, Peripherals and Cabling

In this chapter...

• Telephone Systems— PBXs, Centrex and Key Systems

• Add-on Peripherals for Key Systems, PBXs and Centrex Systems

• ACDs—Specialized Equipment to Handle Large Volumes of Calls

• Media: Wireless, Fiber and Unshielded Twisted Pair Copper

The market for on-site telephone systems such as private branch exchanges (PBXs), key systems and voice mail is highly competitive. Margins are low and growth is slow.

PBXs, Centrex and key systems provide:

• Connections to the public network and to staff at other sites

• The means for on-site personnel to call each other without paying telephone company usage fees

The difference between PBXs and Centrex is in the location and ownership of the equipment that routes calls. Private branch exchanges are located on customers' premises. They are privately owned. Centrex, which stands for central exchange, usually is located at the telephone company and is part of the central exchange, or central office. Customers lease Centrex service from a local telephone company, which owns the switching equipment. Unlike PBXs, the switching equipment is not generally located at customers' premises.

Key systems function much the same as private branch exchanges (PBXs). Key systems generally are smaller than PBXs. They have sophisticated voice mail, call center functionality and support telephones equipped with liquid crystal displays (LCDs) for caller ID and features such as speed dial and redial. Key systems are sold to organizations with fewer than 125 telephones at a site. Systems with 50 to 125 telephones fit into both key system and PBX configurations. The lines of functionality between key systems and PBXs are blurring.

Automatic call distributors (ACDs) route incoming calls to call center agents based on criteria, such as the agent that has been idle the longest. If an agent is not available, the automatic call distributor holds the call in a queue and the caller hears a message such as, “Please hold for our next available agent.” ACDs are sold as part of key systems, Centrex and PBXs and as standalone systems for large call centers. ACDs provide sophisticated reports to help companies determine correct staffing levels and number of outside telephone lines.

Telephone systems with voice over IP (VOIP) capabilities, speech recognition and wireless telephones are in various stages of deployment. Organizations are purchasing IP-based telephone systems in limited quantities. However, experts see potential in the future as organizations start replacing existing telephone and key systems with systems with IP capability. These systems have the potential for lowering the cost of new telephone systems and creating easier, lower cost ways to add new functionality and Internet connectivity to call centers.

The desire for mobility is driving wireless LAN and wireless PBX and key system sales. Just as consumers expect to be able to use their cordless home phones from anywhere within their house, so too are corporate employees starting to use phones and laptop computers at training seminars, meetings and corporate cafeterias. Wireless phones are now in use, which operate in any building within a campus. They provide instant two-way access to staff. Moreover, wireless phones equipped with caller ID enable users to screen calls so that they don't miss important calls.

Speech recognition makes cellular and landline-based telephone access to information more convenient. Airline schedules, weather, AOL email and even mundane information such as corporate directories are easier and faster to access. The speech recognition software is becoming more accurate. Speech recognition eliminates cumbersome menus: for example, “Press 1 for a list of departments; press 2 for a corporate directory.” With speech recognition, callers merely say the department or employee name they wish to reach.

The American Heritage Dictionary (2nd College Edition) defines a medium as “an intervening substance through which something is transmitted or carried.” Telecommunications media are twisted pair copper, commonly used in homes and commercial buildings; coaxial cabling, used in cable TV networks; fiber optics, used for Internet and public network traffic and wireless services. Wireless and fiber optic media have had major impacts on worldwide connectivity. The growth of the Internet and increase in traffic would not have been possible without fiber optics and the electronics, wave division multiplexing (WDM), used to boost fiber optic capacity. The quality and type of media deployed have an impact on capacity, error rates and reliability.