Abstract: A power supply includes a dc voltage source and circuitry which powers a modem data access arrangement (DAA) while preventing dc voltages from being applied to a private line; i.e., the private line is effectively isolated from dc voltages generated by the voltage sources. The circuitry permits ac signals from the modem to travel substantially unhindered over the private line. A first embodiment includes a split winding transformer, and a capacitor coupled across the voltage source. A second embodiment includes a standard transformer, an inductor and a capacitor. A third embodiment includes two capacitors and two inductors. The capacitors are coupled to the inputs of the DAA, while the inductors are coupled between the poles of the voltage source and respective inputs of the DAA.

Abstract: A dense, electronically conductive interconnection layer 26 is bonded on a porous, tubular, electronically conductive air electrode structure 16, optionally supported by a ceramic support 22, by (A) forming a layer of oxide particles of at least one of the metals Ca, Sr, Co, Ba or Mg on a part 24 of a first surface of the air electrode 16, (B) heating the electrode structure, (C) applying a halide vapor containing at least lanthanum halide and chromium halide to the first surface and applying a source of oxygen to a second opposite surface of the air electrode so that they contact at said first surface, to cause a reaction of the oxygen and halide and cause a dense lanthanum-chromium oxide structure to grow, from the first electrode surface, between and around the oxide particles, where the metal oxide particles get incoporated into the lanthanum-chromium oxide structure as it grows thicker with time, and the metal ions in the oxide particles diffuse into the bulk of the lanthamum-chromium oxide structure, to

Abstract: This is a process for producing a ferroboron containing 0.5-20% silicon and up to 4.5% carbon. This process utilizes the silicon reduction of B.sub.2 O.sub.3 and avoids excessive losses due to volatilization of B.sub.2 O.sub.3. It also results in a ferroboron which is substantially free from aluminum impurity. The process uses a mixture, which includes an iron-containing constituent, a silicon containing constituent, and boric acid. Preferably a molten pool is prepared and controlled to a temperature of 1100-1550 (and preferably 1100.degree.-1450.degree. C.) prior to the addition of the boric acid. At least some of the silicon constituent can also be injected into the molten pool along with the boric acid.

Abstract: A method and apparatus are described for automatically placing a modem in the answer or originate mode of operation without the use of a ring detector or a manually operated answer/originate mode selection switch. A timer and two latches are connected in the modem in such a fashion that when the modem is switched into operation it is in the originate mode. For a period of time determined by the timer, the modem looks for the receipt of an answer tone from a remotely located modem. If the answer tone is detected within this time, the modem remains in the originate mode and completes a handshaking sequence with the remote modem. If, however, the answer tone is not received, the modem automatically switches to the answer mode of operation and transmits an answer tone as part of the handshaking sequence.