Abstract: A distributed PBX, KSU and the like system has at least one time domain multiplexed (TDM) switch unit interfaced with transparent wideband channels such as Ethernet by means of at least one Public Switched Telephone Network (PSTN) interface unit and at least one service module (SM) interconnecting it to remote station terminals. One or more applications servers may be located where available or convenient and interact with the TDM switch unit by means of IP addressable path or paths.

Abstract: An improved electrical interconnection between a first circuit board and a second circuit board is provided. In one embodiment, the first circuit board has a substantially rigid circuit portion having a plurality of circuit layers, including a first signal layer, and a first interconnection portion, including the first signal layer, for mating with a second interconnection portion of the second circuit board. The first circuit board also includes a flexible portion, including the first signal layer, for connecting the substantially rigid circuit portion to the first interconnection portion. The flexible portion allows the first interconnection portion to be oriented substantially perpendicular to the substantially rigid circuit portion such that a mating of the first interconnection portion with the second interconnection portion results in a substantially orthogonal electrical interconnection arrangement between the first circuit board and the second circuit board.