Western Electric Company, Inc.

The Frymaster Corporation

Raymond G Taylor

Frying apparatus for frying food, such as French fries, vegetables, bakery goods, meat fish, poultry and the like, in a heated fluid contained in a fry pot. The fluid is heated by a combustion burner that has a heat exchanger removably disposed in the heating fluid. When removed from the fluid, the heat exchanger and the fry pot can be easily cleaned. The air and/or gas is injected into the combustion chamber so as to provide an air gas ratio that supports clean combustion. A control monitors various temperatures and other parameters at various locations of the frying apparatus to control the efficiency of the frying apparatus to approximate a predetermined efficiency by altering the air/gas ratio.

Frying apparatus with closed loop combustion control and method

Line relay contacts (LR1.sub.1, LR1.sub.2) are protected from power surges appearing on a telephone line (L1) during connect or disconnect of a station set (S1) from the line, by operating a hold relay (HR1) to place a hold bridge (HB1) across the line (L1) before energizing the line relay (LR1) to connect or disconnect the station set.

Methods and apparatus for protecting line relay contacts in a telephone

A dialing circuit (10) for an electronic telephone set including a microcomputer (40) having an RAM with two or more memory sections (I and II), each capable of storing data signals representing a telephone number. As the numbers are dialed by operation of a conventional pushbutton dial pad (70), the last number dialed (LND) is stored in RAM section I for automatic redial on operation of a redial key included in the dial pad ('LND,' FIGS. 1-2; 'LND-II' FIG. 3). A mechanism is provided for shifting a first LND from RAM section I to RAM section II, either selectively by operating a Save button (S) in FIGS. 1-2 or automatically on dialing a second number in FIG. 3. An additional key ('S/R,' FIGS. 1-2 or 'LND-I,' FIG. 3) is provided for automatically redialing the first LND from RAM section II. The dialing circuits also include single button (F, P) dialing of a few emergency numbers ('Fire,' 'Police,' '911,' etc.). Preferably, the set is powered solely from the central office line current, and a mechanism is provided (C2) for maintaining the validity of the RAM data for an extended period of at least several hours after the set has been placed on hook.

Dialing circuits and methods for electronic telephone sets

A speech network (11) for a telephone set including a receiver (12) circuit and a transmitter (13) circuit connected in parallel between a tip lead (16) and a ring lead (17). An amplifying transistor (Q4) can be connected in either of two modes, including a normal receive mode for amplifying received signals from the line and applying the amplified receive signal to the receiver circuit. A voice-operated switching unit (Q6,20) is provided for sensing a voice-signal output from the transmitter and connecting the transistor (Q4) in a transmit mode, in which the transistor amplifies the transmitter output for transmission to the line. A sidetone generating circuit (R31, Q5) is connected in parallel with the receiver circuit in the transmit node, for applying a reduced portion of the amplified transmit signal to the receiver.

Speech networks for telephone sets

The loop current (I.sub.X) of a telephone set speech network (1) is automatically initialized at a desired level independent of the central office voltage applied to the input terminals (12, 13) of the set and thus independent of transmission line loop length and other variables. For this purpose, a variable conductance device (20), sush as a Darlington driver (Q1), is connected between the input terminals and the speech network so as to establish a loop current at a circuit node (N1) that is a function of the supply voltage and the conductivity of the device. The loop current is monitored, as by a Schmitt trigger circuit (30), and the conductance of the device (20) is varied accordingly so as to initialize the loop current at the desired level, as by selectively connecting a plurality of resistors (R2 . . . R7) individually and collectively between a base node (26) of the driver (Q1) and the ring lead (17) of the set.

Circuits and methods for initializing the loop current of a telephone set

In the on-hook state of a set of telephone line-switch contacts (LS-1 to LS-5), an incoming low-frequency ringing signal (A) from the central office is rectified (14) and applied to an oscillator circuit (16), which drives the receiver (11) of the telephone handset (21) as the transducer for the tone ringer. A protective switch (20) is used to disable the oscillator circuit from producing an output to the receiver whenever the handset has been lifted from the cradle (22), so as to prevent the user from being rung in the ear if the handset is removed from the cradle and the line switch is thereafter depressed manually while the handset is in the normal listening position. The switch responds to the physical presence of the handset in the cradle, such as by using a magnetically actuated switch mounted in the cradle and operated by a magnet (24) mounted in the facing surface of the handset.

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Shreveport, LA, United States of America

Raymond G Taylor