Abstract: A method of transmitting communication information employing a coding scheme being defined by a character set. The characters of the character set are encoded into codewords of a sequence of bits, the codewords being of varying length. The characters are divided into at least two categories. The categories may be a first category of shifted characters and a second category of unshifted characters. Where a shifted character is encountered during encoding a shift codeword is inserted in the sequence of bits. This allows each category to use overlapping codewords. Then the sequence is converted to ASCII characters to be transmitted.

Abstract: A method of transmitting communication information employing a coding scheme being defined by a character set is disclosed. The characters of the character set are encoded into codewords of a sequence of bits, the codewords being of varying length. The characters are divided into at least two categories. The categories may be a first category of shifted characters and a second category of unshifted characters. Where a shifted character is encountered during encoding a shift codeword is inserted in the sequence of bits. This allows each category to use overlapping codewords. Then the sequence is converted to ASCII characters to be transmitted.

Abstract: A system for determining the state of a container or other enclose space from a remote location is described. A monitoring unit in said container includes a video camera that captures an image of the interior portion of the container. A static image of the interior portion of the container when in an empty state is stored in the monitoring unit. An interrogation request to determine the state of the container from is sent from a client over a network to a control station. The interrogation request is transmitted via satellite from the control station to the monitoring unit. Upon receipt of the interrogation request, the monitoring unit compares the current image of the interior portion with the stored image. A response indicative of the state of vacuity of the container is transmitted back to the control station over a low data rate channel for forwarding to the client. The invention also finds application in security applications where only a low data rate channel is available.

Abstract: Disclosed is an apparatus for improving efficiency in a two-way wireless digital communications system. A predictor predicts the quality of a return link from a remote terminal to a central station from one or more parameters known at the remote terminal. A processor determines an appropriate transmission characteristic for said return link based on said predicted quality. An adjustor adjusts an actual transmission characteristic of said return link to match said appropriate transmission characteristic.