Abstract: A radio LAN (Local Area Network) system includes an access point and a mobile or a fixed station each having a physical layer implemented by a direct spread spectrum system. The LAN system uses different spread codes, maintains transmission power semi-fixed, and selects a frequency and a frequency band in accordance with the kind and amount of information. A data link layer above each physical layer includes an LLC (Logical Link Control) sublayer and an MAC (Media Access Control) sublayer. The MAC sublayer uses a CDMA (Code Division Multiple Access) system as an access system for thereby implementing a data structure in accordance with the kind and amount of information.

Abstract: A radio LAN (Local Area Network) system includes an access point and a mobile or a fixed station each having a physical layer implemented by a direct spread spectrum system. The LAN system uses different spread codes, maintains transmission power semi-fixed, and selects a frequency and a frequency band in accordance with the kind and amount of information. A data link layer above each physical layer includes an LLC (Logical Link Control) sublayer and an MAC (Media Access Control) sublayer. The MAC sublayer uses a CDMA (Code Division Multiple Access) system as an access system for thereby implementing a data structure in accordance with the kind and amount of information.

Abstract: A radio LAN (Local Area Network) system includes an access point and a mobile or a fixed station each having a physical layer implemented by a direct spread spectrum system. The LAN system uses different spread codes, maintains transmission power semi-fixed, and selects a frequency and a frequency band in accordance with the kind and amount of information. A data link layer above each physical layer includes an LLC (Logical Link Control) sublayer and an MAC (Media Access Control) sublayer. The MAC sublayer uses a CDMA (Code Division Multiple Access) system as an access system for thereby implementing a data structure in accordance with the kind and amount of information.

Abstract: A radio LAN (Local Area Network) system includes an access point and a mobile or a fixed station each having a physical layer implemented by a direct spread spectrum system. The LAN system uses different spread codes, maintains transmission power semi-fixed, and selects a frequency and a frequency band in accordance with the kind and amount of information. A data link layer above each physical layer includes an LLC (Logical Link Control) sublayer and an MAC (Media Access Control) sublayer. The MAC sublayer uses a CDMA (Code Division Multiple Access) system as an access system for thereby implementing a data structure in accordance with the kind and amount of information.

Abstract: A radio LAN (Local Area Network) system includes an access point and a mobile or a fixed station each having a physical layer implemented by a direct spread spectrum system. The LAN system uses different spread codes, maintains transmission power semi-fixed, and selects a frequency and a frequency band in accordance with the kind and amount of information. A data link layer above each physical layer includes an LLC (Logical Link Control) sublayer and an MAC (Media Access Control) sublayer. The MAC sublayer uses a CDMA (Code Division Multiple Access) system as an access system for thereby implementing a data structure in accordance with the kind and amount of information.

Abstract: A radio LAN (Local Area Network) system includes an access point and a mobile or a fixed station each having a physical layer implemented by a direct spread spectrum system. The LAN system uses different spread codes, maintains transmission power semi-fixed, and selects a frequency and a frequency band in accordance with the kind and amount of information. A data link layer above each physical layer includes an LLC (Logical Link Control) sublayer and an MAC (Media Access Control) sublayer. The MAC sublayer uses a CDMA (Code Division Multiple Access) system as an access system for thereby implementing a data structure in accordance with the kind and amount of information.

Abstract: A mobile facsimile telecommunications system utilizes an automobile telephone system as a transmission path. In one aspect, this system utilizes an adaptor which can place the facsimile device under an off-hook condition without using an ordinary telephone set additionarily provided to compensate for defects of a portable-type facsimile device having no dialing function, thereby achieving its simplification of system construction as well as the reduction of telephone charges. In another aspect, this system utilizes an automatic response function, a polling transmission function using a given default value, and an automatic off-hook function specified by an operator after conversation, thereby rendering the manipulation for facsimile communication simple.

Abstract: A data transmission apparatus is capable of data transmissions with and/or without error control. A remote data transmission apparatus with error control recognizes whether or not the carrier sent from the data transmission apparatus is intermittent. Additionally, the data transmission apparatus recognizes, based upon the existence of interruptions of a carrier signal sent from a remote data transmission apparatus, whether or not the remote data transmission apparatus has an error control function.

Abstract: A block synchronization data communication unit enables data communication to be properly effected even through a transmission channel under an extremely unfavorable condition as in mobile radio. The block synchronization data communication unit in mobile radio comprises means for encoding data to be transmitted and blocking the encoded data, means for adding a block synchronization signal having a plurality of different successive patterns positioned in a prescribed order to the head of the blocked data, means for transmitting the blocked data added with said block synchronization signal, means for receiving data transmitted, means for recognizing one of patterns constituting the block synchronization signal in the received data, means for estimating the data position based on a block synchronization signal constitution position of the recognized pattern, and means for decoding the blocked data beginning from the estimated position as received data.

Abstract: A line switching control system effects switching between a data communication mode and a voice communication mode in mobile communication, particularly mobile telephone service. The line switching control system includes a transmitter/receiver unit for transmitting and receiving signals through an antenna, an input device combined with a telephone, a switching device for effecting switching between the data communication mode and the voice communication mode, and a control unit for controlling switching between the data communication mode and the voice communication mode based on a mode switching command entered through the input device. When a key of the input device at the user's hand is depressed, switching between the data communication mode and the voice communication mode can smoothly be performed.

Abstract: A request repeat system for data communication in which the receiving station transmits a signal indicating the result of reception of data transmitted thereto from the transmitting station. The receiving station transmits a signal indicating the unsatisfactory data reception repeatedly N times at the maximum until the receiving station is able to receive the data normally to request the transmitting station to transmit the data again, when the receiving station does not receive the data in a prescribed time after the receiving station has transmitted the signal indicating the unsatisfactory reception of the data to the transmitting station. Thus, the request repeat system eliminates useless communication charge necessary for restarting data communication after interruption and repetition of operation for requesting the repeated transmission of data, and hence the request repeat system is particularly effectively applicable to mobile data communication.

Abstract: A block synchronization data communication system enables data communication to be properly effected even through a transmission channel under an extremely unfavorable conditions as in mobile radio such as automobiles. The block synchronization data communicating system comprises the steps of encoding data to be transmitted and blocking the encoded data, adding a block synchronization signal having a plurality of different successive pattern positioned in the prescribed order to the head of said block data, transmitting the block data added with said block synchronizing signal, receiving said transmitted data and recognizing one of said patterns constituting the block synchronizing signal, estimating the data position based on a block synchronization signal constitution position of the properly recognized pattern, and decoding the block data beginning from said estimated position as received data.