Abstract: An improved communication method and apparatus for communicating between a first object and a second object wherein the first object includes apparatus for generating and transmitting a modulation signal having at least a predetermined number "L" pulses within a predetermined time interval and less than a predetermined number "M" pulses within the same predetermined time interval, and wherein the second object includes apparatus for receiving and detecting the modulation signal and providing an output signal in response to detecting at least the predetermined number "L" a pulses and less than the predetermined number "M" pulses. ThisCROSS-REFERENCE TO RELATED APPLICATIONSthis application is a division of the Applicant's co-pending application entitled "COMMUNICATION APPARATUS FOR COMMUNICATING BETWEEN A FIRST AND A SECOND OBJECT," Ser. No. 462,247, filed Apr. 19, 1974 and now U.S. Pat. No.

Abstract: An improved communication apparatus for communicating between a first object and a second object wherein the first object includes apparatus for generating and transmitting a transmit signal and the second object includes apparatus for receiving the transmit signal and providing an emitted signal in response thereto, the emitted signal having a frequency coherently related to the frequency of the received transmit signal. The second object also includes an apparatus for encoding an identifying code having a unique code format wherein the beginning and the end of the code format are identifiable, the first object including apparatus for receiving the encoded emitted signal, identifying the code format encoded therein and determining the received emitted signal represents a valid code format.

Abstract: A priority control valve for the priority steering control and the auxiliary circuits of the hydraulic system of a fork lift truck or the like characterized in that the housing interchangeably accommodates different priority flow control spools according to the type of steering control valve which is used i.e. a closed center steering control valve with a variable meter-in orifice in the pressure feed circuit or a closed center steering control valve with a variable meter-out orifice in the steering cylinder return circuit or an open center steering control valve with an orifice in the priority flow divider spool to determine the priority circuit flow by controlling a variable displacement pump when the priority circuit itself is operated or when the priority circuit load pressure is greater than the load pressure of the auxiliary circuit.