Abstract: In a PBX environment, a middleware module abstracts communication cards so that the plurality of channels associated therewith are grouped for efficiency. The middleware module recognizes unoperational channels, and restarts the hardware associated with the channels as well as allowing conferencing and transferring calls when the PBX switch does not support same. Preferably, for outgoing calls, the middleware adapter controls the state of interfaces for all hardware adapters and tries to deliver calls over active interfaces. In case of failure, the middleware adapter investigates and makes a decision if the call should be delivered over another adapter. In this way, redundant and highly available solutions are implemented transparent to application and interface drivers. For incoming calls, the middleware adapter accepts calls from all hardware adapters and presents these calls to applications as if these calls are issued by one adapter.

Abstract: A communication adapter having a multi-layered abstracting protocol implementation to facilitate communication between a low level unified protocol module and a low level abstraction protocol module of the communication adapter. The communication adapter has a virtual signaling architecture that allows use of one API supporting multiple network architectures. An abstraction layer, at the lower interfaces, converts the higher layer API for the different network architectures and provides the ability for a single application to be used in many different network topologies including traditional telephone networks and VoIP networks.