Abstract: A wireless product for wireless communication is constructed for spread spectrum operation within a required channel bandwidth where an RF signal for transmission in the channel is divided into sub-channels, each of which is less than the minimum channel bandwidth permitted by FCC regulations in order to realize improved transmission characteristics and greater flexibility in transmission timing and synchronization. The wireless product includes a controller for controlling system operation. During operation, the RF signal portion is less than the minimum channel bandwidth required by said regulations thus dividing the channel bandwidth to form N sub-channels, and setting the bandwidth of the RF signal to be substantially equal to the sub-channel bandwidth. The RF signal portion being transmitted in each of the N sub-channels.

Abstract: A security system in which wireless transmitting security devices use a hybrid or dual encoding methodology, wherein a first part of a data message is encoded in a return-to-zero (RZ) format and a second part of the data message is encoded in a non-return-to-zero (NRZ) format, thereby increasing error detection and correction. In a first aspect of the invention, status information is included in the first part of the message and redundant status information is included in the second part of the message. In a second aspect of the invention, message sequence information is included in the second part of the message to avoid processing of stale or out-of-sequence messages.

Abstract: A security system in which wireless transmitting security devices use a hybrid or dual encoding methodology, wherein a first part of a data message is encoded in a return-to-zero (RZ) format and a second part of the data message is encoded in a non-return-to-zero (NRZ) format, thereby increasing error detection and correction. In a first aspect of the invention, status information is included in the first part of the message and redundant status information is included in the second part of the message. In a second aspect of the invention, message sequence information is included in the second part of the message to avoid processing of stale or out-of-sequence messages.

Abstract: A wireless product for wireless communication is constructed for spread spectrum operation within a required channel bandwidth where an RF signal for transmission in the channel is divided into sub-channels, each of which is less than the minimum channel bandwidth permitted by FCC regulations in order to realize improved transmission characteristics and greater flexibility in transmission timing and synchronization. The wireless product includes a controller for controlling system operation. During operation, the RF signal portion is less than the minimum channel bandwidth required by said regulations thus dividing the channel bandwidth to form N sub-channels, and setting the bandwidth of the RF signal to be substantially equal to the sub-channel bandwidth. The RF signal portion being transmitted in each of the N sub-channels.

Abstract: A security system in which wireless transmitting security devices use a hybrid or dual encoding methodology, wherein a first part of a data message is encoded in a return-to-zero (RZ) format and a second part of the data message is encoded in a non-return-to-zero (NRZ) format, thereby increasing error detection and correction. In a first aspect of the invention, status information is included in the first part of the message and redundant status information is included in the second part of the message. In a second aspect of the invention, message sequence information is included in the second part of the message to avoid processing of stale or out-of-sequence messages.

Abstract: A method of authenticating a security device to determine if it is authorized to be used with a security system. First and second encryption keys are stored in the control panel and the security device. A challenge message is produced by encrypting, with the first key, a challenge index (such as a random number generated by the control panel). The challenge message is transmitted the security device, where the encrypted challenge index is extracted from the challenge message and then decrypted using the first key at the security device to produce a response index. A response message is produced by encrypting, with the second key, the response index decrypted by the security device. The response message is transmitted to the control panel, and the encrypted response index is extracted and then decrypted using the second key at the control panel to produce the response index. The control panel then compares the response index with the challenge index previously generated.

Abstract: The invention relates to a shaft preheater for preheating material in lump form with at least one shaft for receiving the material, a bridge disposed in the shaft for delivering hot gases which flow through the material from the bottom upwards, and a device for filling the shaft with the material such that the shaft is charged centrally thereby developing a filling cone. The bridge is disposed at an inclination corresponding to the filling cone in order to guarantee an even flow through the fill. The device for filling the shaft comprises a vertically adjustable feed chute.

Abstract: A security system in which wireless transmitting security devices use a hybrid or dual encoding methodology, wherein a first part of a data message is encoded in a return-to-zero (RZ) format and a second part of the data message is encoded in a non-return-to-zero (NRZ) format, thereby increasing error detection and correction. In a first aspect of the invention, status information is included in the first part of the message and redundant status information is included in the second part of the message. In a second aspect of the invention, message sequence information is included in the second part of the message to avoid processing of stale or out-of-sequence messages.

Abstract: A method of authenticating a security device to determine if it is authorized to be used with a security system. First and second encryption keys are stored in the control panel and the security device. A challenge message is produced by encrypting, with the first key, a challenge index (such as a random number generated by the control panel). The challenge message is transmitted the security device, where the encrypted challenge index is extracted from the challenge message and then decrypted using the first key at the security device to produce a response index. A response message is produced by encrypting, with the second key, the response index decrypted by the security device. The response message is transmitted to the control panel, and the encrypted response index is extracted and then decrypted using the second key at the control panel to produce the response index. The control panel then compares the response index with the challenge index previously generated.

Abstract: The invention relates to a shaft preheater for preheating material in lump form with at least one shaft for receiving the material as well as a bridge disposed in the shaft for delivering hot gases which flow through the material from the bottom upwards. The bridge is disposed at an inclination in order to guarantee an even flow through the fill.