The ferreed — A new switching device

An experimental switching device is described that has the following properties: (a) sealed metallic contacts, (b) control times in the microsecond range, (c) coincident selection, (d) memory without holding power and (e) small size. The device, named the ferreed, may be used as a crosspoint in telephone switching networks of the space-separation type. The development of the ferreed is traced from a conceptual model, through realization of a practical model, to possible applications in switching networks. Two methods of coincident control are discussed, and three devices related to the conceptual ferreed are described briefly.