Overview

PBX common equipment can be divided into two main hardware categories: cabinets and printed circuit cards. There are many cabinet and card category types, and each PBX system model is designed and configured with the use of unique and proprietary hardware equipment. Neither cabinets nor cards are interchangeable between different PBX systems from different manufacturers. Proprietary common equipment hardware is currently the major reason the open design platform of new IP-PBX client/server systems is attracting the attention of many customers. Although the industry trend is toward reduced dependence on proprietary common equipment, the very large installed base of traditional PBX systems will guarantee the continued requirement for new equipment cabinets and port circuit interface cards for many years to come.

The PBX starter package is usually called the main system assembly and includes the necessary hardware elements and software for basic system operation. Small port size customers may require only a single cabinet equipped with all of the necessary equipment to support their station and trunk interface needs, but very large port size customers may require a dozen or more colocated or distributed cabinets. For any specific customer port size requirement, common equipment costs are relatively fixed regardless of feature or function requirements because the same core hardware components that support plain old telphone system (POTS) applications are required for advanced call center or networking applications. The advanced application configurations may include adjunct application servers, but the common equipment hardware supporting port station and trunk requirements is usually...