Abstract: In an example embodiment, a system comprises a chain of serially coupled nodes, including a central processing node (CPN) and one or more radio communications nodes (RCNs). The CPN couples to a first RCN in the chain via a dielectric waveguide (DWG) link and any further RCNs in the chain are successively connected in serial fashion from the first RCN via further (DWG) links. The CPN generates outbound radio carrier signals that are waveguide-propagated in a downstream direction of the chain, for over-the-air (OTA) by targeted ones of the RCNs, while radio carrier signals received via OTA reception by respective ones of the RCNs are waveguide propagated as inbound radio signals in an upstream direction of the chain, for processing by the CPN. Advantages from he contemplated system include greatly simplified implementation of the RCNs, with lower cost and power consumption. Further, strategic placement of failover CPNs and DWG links provide for continued operation in the face of CPN or DWG link failures.

Abstract: An ejector pump has a ringshaped nozzle slot directed radially outwards followed by a radially directed mixing zone interacting with a secondary channel and a radially directed diffuser slot.To achieve an improved performance, and especially one having a characteristic less dependent to decreases of working medium pressure the ejector pump is comprised of two mutually fixed blocks (1, 2) having each an end surface (4, 6). Said end surfaces (4, 6) are facing each other forming an annular slot (12). The surfaces of the nozzle slot and the diffuser slot are profiled in at least one of said end surfaces (6) separated by an annular groove (7) in said end surface, which groove (7) communicates with the secondary channel. The diffuser slot height adjacent the groove (7) is larger than the nozzle slot height (h.sub.o) adjacent said groove decreasing outwardly by the way of at least two bevels, first one having an angle of bevel .alpha..sub.1 =8.degree.-15.degree. and then one having an angle of bevel=4.degree.-8.