Abstract: Cable modems are provided for measuring a noise signal power level on the upstream side of the cable network. The cable modem may be configured to make the signal power measurements at a variety of frequencies and at a selected bandwidth during a specified test time period responsive to a request received from the cable network. Methods and systems are provided for identifying a noise signal source on a cable network including specifying a time window for measurements, the desired measurements and the cable modems from which measurements are desired when the need to initiate a test to identify a noise source is detected. Tests may be initiated based on noise signal measurements by individual cable modems or by the cable services provider which indicate an unacceptable noise level. In addition, the reliability of the test measurements may be improved by not allowing any transmissions on the upstream side during the concurrent test window while cable modems are making the requested measurements.

Abstract: A cable modem blocks data transfers addressed to host systems during a safe mode of operation and provides the data transfers to the addressed host systems during a normal mode of operation. The cable modem can be coupled to multiple host systems which can be addressed separately. Accordingly, the safe mode of operation can be selected for a subset of the host systems coupled to the cable modem. The safe mode or normal mode of operation can be invoked by pushing a button on the cable modem. The safe mode of operation may also be invoked after the expiration of a timer which times an interval of inactivity at the host. The normal mode of operations can be invoked after detecting activity at the host system.

Abstract: An email service provider includes a port receiving and transmitting email, and a server. The server selectively creates a dynamic address as the sending address associated with email transmitted to a target address, with the dynamic address being anonymously associated with the first user address. The server may further selectively forward email addressed to the dynamic address to the first user address, by forwarding mail to the dynamic address only when it is from the target address, and/or by forwarding only a selected amount of mail to the dynamic address and/or for only a selected period of time. The server may also include a tag in the dynamic address associated with the target address, and add the tag to text of received email addressed to the dynamic address.

Abstract: The security of wireless communications between two or more devices is enhanced by requiring detection of the physical proximity of the devices. One or more of the devices operates in a non-secure mode, wherein the authentication process required to enter into secure communications is disabled. Upon detection of the physical proximity of another device, the device enters a secure mode, wherein authentication is enabled. The entry of a security code required by the authentication process may comprise the transmission of a device address or other data, either across the proximity detection interface or via the wireless communications interface. In addition to the detection of physical proximity, a hardware handshake protocol between the two devices may be defined. For additional security, the device must enter a handshake mode before the hardware handshake will complete. The handshake mode may require entry of a password or screening by a biometric sensor.

Abstract: In a digitally trunked radio repeating system that may include several radio site repeating transceivers, a site area identification coding system to ensure that transmissions intended for one site or as one mode are not decoded by another site or as another transmission mode. In particular, a site or transmission mode identification byte is used in the transmission error coding (CRC) scheme applied by both a mobile transceiver and the radio site repeater. Since the identification byte is used in the transmitter to calculate the CRC error correction data, the same identification byte must be used in the receiver to decode the CRC value. The intended radio site or transmission mode wilt apply the proper identification byte to decode a transmission. The wrong radio site or mode will not correctly decode the CRC value in a transmission because the wrong identification byte will be applied to the transmission.

Abstract: A digitally trunked radio repeater system provides substantial improvements in timeliness and reliability. The mobile radio transceivers transmit channel requests on the control channel at 9600 bps. The mobile transceiver switches to a working channel in response to an assignment message received on the control channel. Message and transmission trunking capabilities are both present so as to maximize working channel usage without compromising channel access for high priority communications. Radios select between message and transmission trunking based on over-the-air signaling. During transmission trunking, called and calling receivers return to the control channel after each transmission (and called transceivers may be inhibited from transmitting) but grant higher priority to calls from the other transceivers being communicated with to ensure continuity over an entire conversation.

Abstract: Intelligibility of received speech in a radio receiver is improved by automatically adjusting audio response in accordance with ambient noise levels. When high ambient noise is present, the relative gain of the higher audio frequencies is increased at the expense of low frequency response. In this instance, some "naturalness" is traded for the higher intelligibility provided by increased high frequency gain. The ambient noise level is determined based on either a volume level or a direct sample of ambient noise by a microphone. An audio response message is built in accordance with the ambient noise level, and a digital signal processor adjusts the audio response of the radio receiver in accordance with the audio response message.

Abstract: A digitally trunked radio repeater system provides substantial improvements in timeliness of channel acquisition and channel drop, and in reliability of critical control signalling. The system uses a much higher digital signalling rate than is typically found in prior art systems, and uses a control channel to convey digital channel request and assignment messages between the central site and mobile transceivers. The mobile radio transceivers transmit channel requests on the control channel (if no response is received, the mobile retries during a retry time window which increases in duration in dependence on the number of retries). The mobile transceiver switches to a working channel in response to an assignment message received on the control channel. Subaudible digital signals transmitted on the control channel and on active working channels allow late entry, shifting to higher priority calls, and other advanced functions.

Abstract: A hardware-software security arrangement enables manufacturers of digital RF communications equipment to provide differently configured products having substantially identical hardware and operational control software. Only authorized units are permitted to activate software-controlled "optional" features. The software is protected against unauthorized modifying, copying and uploading/downloading. The security arrangement allows a manufacturer to control the distribution of functional features and operational software upgrades by requiring a product-specific authorization. Each individual unit has a read-only storage device containing a unique device-specific value. "Checksum" data is uniquely computed by the manufacturer for each individual product unit according to a "feature authorization code" specifying particular authorized functional features and the device specific value by using a particular data transformation. This computed data is stored in the unit.

Abstract: A digitally trunked radio repeater system provides substantial improvements in timeliness of channel acquisition and channel drop, and in reliability of critical control signalling. The system uses a much higher digital signalling rate than is typically found in prior art systems, and uses a control channel to convey digital channel request and assignment messages between the central site and mobile transceivers. The mobile radio transceivers transmit channel requests on the control channel (if no response is received, the mobile retries during a retry time window which increases in duration in dependence on the number of retries). The mobile transceiver switches to a working channel in response to an assignment message received on the control channel. Subaudible digital signals transmitted on the control channel and on active working channels allow late entry, shifting to higher priority calls, and other advanced functions.

Abstract: A digitally trunked radio repeater system provides substantial improvements in timeliness of channel acquisition and channel drop, and in reliability of critical control signalling. The system uses a much higher digital signalling rate than is typically found in prior art systems, and uses a control channel to convey digital channel request and assignment messages between the central site and mobile transceivers. The mobile radio transceivers transmit channel requests on the control channel (if no response is received, the mobile retries during a retry time window which increases in duration in dependence on the number of retries). The mobile transceiver switches to a working channel in response to an assignment message received on the control channel. Subaudible digital signals transmitted on the control channel and on active working channels allow late entry, shifting to higher priority calls, and other advanced functions.

Abstract: A digitally trunked radio repeater system provides substantial improvements in timeliness of channel acquisition and channel drop, and in reliability of critical control signalling. The system uses a much higher digital signalling rate than is typically found in prior art systems, and uses a control channel to convey digital channel request and assignment messages between the central site and mobile transceivers. The mobile radio transceivers transmit channel requests on the control channel (if no response is received, the mobile retries during a retry time window which increases in duration in dependence on the number of retries). The mobile transceiver switches to a working channel in response to an assignement message received on the control channel. Subaudible digital signals transmitted on the control channel and on active working channels allow late entry, shifting to higher priority calls, and other advanced functions.

Abstract: A digitally controller radio transceiver includes a housing including a front cover provided with a display port; a main controller board mounted within the housing; an optional display board attached to an interior surface of the front cover adjacent said display port, said display board electrically connected to said main controller board by a pressure fit connection; a removable display escutcheon plate mounted on an exterior surface of the cover, overlying the display port; and fastening means extending through the cover and connecting the display board to the display escutcheon plate. Removal or omission of the display board is automatically sensed by the radio transceiver's internal microprocessor which operates accordingly. In one embodiment the transceiver program store may be loaded via an external connector to customize the microprocessor instruction code for the presence or absence of a display.

Abstract: A digitally trunked radio repeater system provides substantial improvements in timeliness of channel acquisition and channel drop, and in reliability of critical control signalling. The system uses a much higher digital signalling rate than is typically found in prior art systems, and uses a control channel to convey digital channel request and assignment messages between the central site and mobile transceivers. The mobile radio transceivers transmit channel requests on the control channel (if no response is received, the mobile retries during a retry time window which increases in duration in dependence on the number of retries). The mobile transceiver switches to a working channel in response to an assignment message received on the control channel. Subaudible digital signals transmitted on the control channel and on active working channels allow late entry, shifting to higher priority calls, and other advanced functions.