Abstract: A headset (10) for a radiotelephone (12) has a boom (16) that pivots about a housing (13). The headset (10) has a speaker (20) and a microphone (18). A headset detect circuit (33) determines when the headset connector (24) has been plugged into the radiotelephone's jack (26) and signals the microprocessor (60). The microprocessor (60) then connects the transmitter (68) and the receiver (70) to the headset's microphone (18) and speaker (20). To answer a call the user rotates the boom (16), either clockwise or counter clockwise, which closes a three position switch (30) and sends an off-hook signal (44) to a microprocessor (60).

Abstract: The extended error correction process of the present invention error corrects a data message that has been transmitted a plurality of times. The process first receives the data message at least twice, logically combining the first and second messages received to form an error indication word. The error indication word is then used to locate the error locations in each message after which some of the errors are complemented, depending on the total number of errors found. The message is then decoded and used for transmit power changes, channel reassignment, to release a call, etc.

Abstract: A battery charger (10) and associated method for maintaining the charge of a battery (12). The battery charger (10) has a processor (16), power supply (14) and power regulator (15). The battery charger (10) first applies a high current charge to the battery (12), which is terminated when the battery voltage or temperature reaches a defined limit. Then the battery charger (10) applies a low current charge (102) for a set period of time. Next, no charge is applied until the battery (12) cools to an ambient temperature. The ambient temperature is then measured using a thermistor (18) in the battery (12). If the ambient temperature is above a certain threshold no charge is applied for a wait period. If the ambient temperature is below the threshold the low current charge is applied for a the set period of time.

Abstract: A method for providing two-way calling between first and second handsets (402, 404) using a base station (406) and a paging terminal (412). The method for making the call includes storing a base line phone number for each line within the base station (406). A communication link is established between the first handset (402) and the base station (406) and between the base station (406) and the paging terminal (412). The paging terminal (412) prompts the caller for information to be sent to the second handset and the caller responds by entering a sequence that allows the base station itself to forward the base line phone number and an alias code, representing the identification of the first handset, to the paging terminal (412). The paging terminal (412) then pages the second handset (404) with the base line phone number and the alias code.

Abstract: The process of the present invention error corrects sub-audible data words that have been transmitted over a voice channel. A data word may be transmitted up to three times if an acknowledge is not received by the transmitter. If any of the three possible repeats of the received data word are decodable, an acknowledgment is transmitted. If all three repeats of the data word contain uncorrectable errors, a bitwise majority vote is performed on the three data words. If the result of the majority vote is decodable, an acknowledgement is transmitted to the sender.

Abstract: A DC translation circuit (200) provides maximum dynamic range in DC level shifting that is temperature and process invariant. The DC translation circuit (200) includes a bandgap reference (202) and current mirror circuit (204) for providing a reference current, Iref. An op-amp circuit (210) receives an AC signal centered about a first DC level, and translates the first DC level into a second DC level using the reference current, a current mirror circuit (208), op-amp circuit (210) and resistor (R2).

Abstract: A cellular cordless telephone may receive cellular telephone calls via a cellular telephone system and receive telephone calls on a system having a limited radio coverage area. To reduce the amount of time spent in monitoring the sub-data channel of the limited coverage area system, a timing signal is generated which represents the period of time spent monitoring the radio channel. During the monitoring, a predetermined number of data words transmitted on the limited radio coverage area radio channel system are received. When a first received data word is detected, an allowed monitoring time value is adjusted to be the sum of the value of the timing signal and the product of a determined number of received words to be detected and the time required for each word. This adjusted value of the monitoring time value is compared to the value of the timing signal and when the adjusted monitoring time value equals or exceeds the timing signal value, the monitoring of the radio channel ceases.