Abstract: Two-wire signal transmitter and method in which a very low-level Alternating Circuit (AC) input signal sensed at a remote circuit at a first end of a signal path is added to a low-level Direct Current (DC) bias signal provided by a local circuit that is located at a second end of the signal path. In a preferred embodiment, the remote circuit is electrically coupled to and powered by the local circuit through a two-wire path interconnection, typically a shielded twisted-pair cable. The DC bias signal has sufficient level to overcome minimum ratings of electrical contacts, thereby to pass the sensed very low-level AC input signal reliably through the poor electrical contacts that are used, for instance, for connecting electronic circuits that run the length of a railway train.

Abstract: A unitary mold member for shaping glass includes an inner surface which shapes molten glass blown thereagainst and an outer surface. A cavity within the unitary mold member is positioned between the inner and outer surfaces. The unitary mold member has passages at about the upper end thereof between the cavity and the surrounding atmosphere. The unitary mold member also has passages at about the lower end thereof between the cavity and the surrounding atmosphere.