Abstract: A communication device (1) comprising a receiver (2) for receiving coded messages transmitted on one or more channels. There is a micro-processor (13), in communication with the receiver (2) and a frequency synthesizer (4) coupled to both the micro-processor (13) and the receiver (2) to thereby control reception of the channels. The communication device (1) also has a memory (14) storing a group of-channel frequencies, wherein the micro-processor (13) is adapted, in combination with the frequency synthesizer (4), to control the receiver (2) to scan at least some of the channels during baud detect periods of a protocol cycle associated with at least one of the channels. Further, the micro-processor (13) cyclically offsets a start of the baud detect periods after completion of a protocol cycle.

Abstract: A method by which a data communication receiver may recognize a specific channel comprises the steps of receiving (1605) a data stream on a first channel for a first amount of time to determine (1680) whether network identification information is included in the data stream received on the first channel, wherein the network identification information comprises at least one address assigned to represent a network. If the network identification information is not included in the data stream received on the first channel within the first amount of time, reception is switched (1614) to receive (1605) a data stream on a second channel. The method further comprises the step of receiving (1605) the data stream on the second channel for a second amount of time to determine (1680) whether the network identification information is included in the data stream received on the second channel.

Abstract: A method and apparatus select a receive frequency of a receiver (400) in a system having coverage areas divided into zones. A primary scan list is stored in the receiver (400) and contains coverage area identification parameters. The list is initially ordered from a most frequented coverage area at the top to a least frequented coverage area at the bottom. The parameters can include a coverage area identifier and a zone identifier, and at least one corresponding frequency identifier. A frequency identifier is chosen (604) from the top of the list and the receiver (400) is tuned to the receive frequency identified thereby. Baud rate detection is performed (608) and, in response to finding a predetermined baud rate, a received coverage area identifier and/or a received zone identifier is decoded (612). If the received identifier matches a corresponding parameter stored in the receiver, the receiver (400) is locked (904) to a signal on the receive frequency.

Abstract: Group call capability is provided as for a digital pager having a two word page address and using asynchronous detection. A group call is initiated by transmitting two identical binary words having an extra bit space between them, the binary word being word one of the individual paging address of each unit in the group to be called.

Abstract: An improved detection arrangement for detecting the presence of a given tone in a received input signal. A reference generator, in the form of a reference clock and a programmable divider, produces a first reference frequency, equal to the frequency of the tone, and at an arbitrary phase angle thereto. A second generator output is in quadrature to the first. Each reference signal is product detected with the input signal via exclusive OR gates.A unique digital low pass filter, operating in a time multiplex mode, receives the gate outputs, removes all high frequency components therefrom, and produces pairs of output binary number encoded signals, each of which is representative of a vector component of a detected tone. Threshold detector circuitry monitors the outputs indicating an above threshold condition at its output in response to predetermined combinations of the binary numbers. The combinations represent all input vectors whose resultant absolute magnitude exceeds a chosen threshold.