A battery charger/monitor circuit for charging and/or monitoring a plurality of series-connected cells, including a voltage sensor for sensing the voltage across each of the cells to provide a high cell voltage signal proportional to the highest voltage across any of the cells and a low cell voltage signal proportional to the lowest voltage across any of the cells. The circuit is operable in a monitor mode or a charge mode. In the monitor mode, the cells are disconnected from a load if the low cell voltage signal decreases to a first predetermined level. The circuit includes a controller which provides a control signal in response to the high cell voltage signal, the low cell voltage signal and a current sense signal, for controlling the charging of the cells. In the charge mode, the cells receive a constant charge current until the high cell voltage signal reaches a second predetermined level, after which the voltage across the cell charged to the highest voltage is held substantially constant, causing the charge current to be reduced.

Voltage sensor for detecting cell voltages

According to one embodiment, a method includes determining an orientation of a portable communication device and controlling an aspect of the operation of the portable communication device based on the determined orientation.

Method and system for controlling a portable communication device based on its orientation

A push-to-talk controller in a wireless network, comprising a presence server and a push-to-talk server, establishes a local ad hoc group session between an inviting mobile terminal and local mobile terminals responsive to a push-to-talk request from the inviting mobile terminal. The presence server identifies local mobile terminals within a local area of the inviting mobile terminal. The push-to-talk server then establishes the group session between the inviting mobile terminal and one or more local mobile terminals in the local area. In exemplary embodiments, the push-to-talk server sends an invite message to each of the local mobile terminals identified by the presence server and establishes the local ad hoc group session between the inviting mobile terminal and one or more of the local mobile terminals that respond to the invite message.

METHOD FOR PoC INSTANT TEMPORARY GROUP CHAT BASED ON PRESENCE AND LOCATION

Systems and methods for restricting the use and movement of telephone system devices are presented. The system includes an interface configured to allow telephone calls to a limited set of telephone numbers or area codes. The interface may be configured to detect a number during a call attempt and compare the number to a stored sequence list of allowed numbers. If the detected number matches one of the allowed numbers, the call attempt is allowed to continue. However, if the detected number does not match a number in the stored sequence list, the call attempt is blocked. The interface may also be configured to restrict the movement of a cellular telephone based on received location data, configured with a physical lock to prevent removal from a docking station, or configured to generate a locking signal inhibiting use of the telephone after it has been moved greater than the predetermined distance.

Systems and methods for restricting the use and movement of telephony devices

A visual interface for a PTT user terminal (20) displays user images of participants in a PTT conference. When a PTT conference is established, a controller (22) determines whether an image associated with each participant invited to the PTT conference is stored in memory (24) on the user terminal (20). For each participant that has an associated image stored on the user terminal (20), the controller (22) displays the image. For those participants that do not have an associated image stored on the user terminal, the controller generates and sends a request for the image. Upon receipt of the image, the controller (22) displays the image on the user terminal (20). During the PTT conference, the controller (22) alters the appearance of the images to show the status information of each participant, such as which participant has floor control and presence of participants.

Image exchange for image-based push-to-talk user interface

A method for providing full duplex dispatch operation includes the step of establishing a dispatch call ( 102 ) and determining if a full duplex dispatch mode is desired ( 104 ). If full duplex dispatch operation is selected, a signal is sent to the communication system requesting that full duplex dispatch operation is requested. The communication system then provides the necessary channel resources to allow for full duplex dispatch operation ( 106 ). In another embodiment, the radio user can select full duplex dispatch mode ( 202 ) prior to call setup. A radio ( 310 ) capable of providing both half duplex and full duplex dispatch operation is also described.

Method and apparatus for providing full duplex dispatch

A moveable antenna system with a position sensor circuit and a circuit which transmits the position sensing data and the radio frequency (RF) on the same wire. The position sensor comprises a sensing pin and a sense track concentric with the coaxial cable for the RF signal. When the antenna is in the preferred position for transmission, the sensing pin is in contact with the sense track, thus closing a switch, allowing the unit to transmit RF signals. Otherwise, the sensing pin is not in contact with the sense track, preventing any transmission of data. The signal that results from the opening and closing of the switch is carried on the same transmission line as the RF signal. This is accomplished by using capacitors to block direct current (DC) from the transmission line and using resistors and shunt capacitors to prevent any leakage of RF signals onto the sensing circuit.

Moveable antenna employing a hybrid RF and DC circuit

A hand-held communication device with vertically oriented antenna includes a housing with a main body and a cover hingedly attached to the main body for movement between a closed position and an open position. The main body has a control surface enclosed by the cover in the closed position and accessible for operation with the cover in the open position. An antenna is movably affixed to the cover so as to form a portion of the cover with the cover in the closed position and to extend generally vertically from the cover with the cover in the open position and the communication device housing held in an operative orientation.

Hand-held communication device with vertically oriented antenna

A power shutdown circuit includes an electronic latch circuit connected in series with a monitored power supply and comparator input and power terminals. The output terminal of the comparator is coupled to the control terminal of the latch. When a monitored signal magnitude crosses a threshold, the comparator provides a control signal which renders the latch nonconductive. A main switch device also connected to an output of the latch responds to the nonconductive state thereof to remove power from an electrical load.

Threshold detecting battery protection circuitry

A system, method and computer readable medium for facilitating call setup on a wireless device is disclosed. The method on a push-to-talk wireless device includes receiving a talk request from a user of the wireless device. The method further includes receiving and storing audio in memory. The method further includes initiating a connection setup procedure with a wireless network and receiving a message from the wireless network indicating establishment of a connection. The method further includes transmitting to the wireless network the audio stored in the memory of the wireless device, wherein the step of receiving audio from the user occurs before the step of receiving a message from the wireless network.

David Edwards

Papers

Method and apparatus for providing full duplex dispatch

Moveable antenna employing a hybrid RF and DC circuit

Hand-held communication device with vertically oriented antenna

Threshold detecting battery protection circuitry

Voice buffering during call setup