Abstract: A display system comprises a display apparatus such as an electronic notice board, TV set or computer monitor. Radio messages are received by a point-to-point receiving apparatus, such as a wide area digital pager, adjustably mounted relative to the display apparatus. The receiving apparatus generates non-electrical signals which are transmitted to the display apparatus, the display apparatus displaying said signals. The receiving apparatus is adjusted to minimize the error rate in the signal received by said apparatus.

Abstract: A point to point communication apparatus, such as a digital radiopager (RP), having a non-volatile electrically programmable store which stores a radio identification code (RIC) or apparatus configuration information. The store can be programmed/reprogrammed by sending coded light signals to a light sensor. The coded programming/reprogramming light signals are supplied from an external source, such as a personal computer, and conform to a protocol which on being recognized causes a controller to permit access to the programmable store. The light sensor may also be used to sense the ambient light and control energization of a back light of a LCD panel.

Abstract: A communications receiver such as a radiopager derives information which is necessary for operation thereof from a discardable read-only data card which is inserted therein. Such information may include a radio identity code (RIS) for relating the receiver to a particular user, and prepaid credit units which are cancelled by the receiver based on the number of received messages or time intervals of operation thereof. The information may also include a particular frequency and data rate for adapting the receiver to operate on a paging system used in a particular country. Once the information on the data card has been read-out and stored in a non-volatile store, the card can be removed and either discarded or recharged with new credit units upon payment of a fee at an authorized station. The receiver may be adapted for use in a different country simply by inserting a data card relating to that country, paying for usage of the receiver as the user goes from country to country.

Abstract: A pager decoding system which is suitable for use with signal formats, such as POCSAG, in which code words are sent in batches, each batch containing a synchronization code word and (n-1) address/message code words, n being the number of code words in a batch, each code word comprising m bits.The pager is able to detect or regain synchronization code word when the carrier signal is lost due to fading.When synchronization is lost input data received by the pager is combed through by switching-on the pager for a duration of m bits at intervals corresponding to (n+1) code words. The data received is stored in a shift register having m stages and in which a synchronization code word can be assembled within two batch periods. Once the synchronization code word has been detected the pager can be switched to a normal data receive mode.In another fade recovery mode the (m-1)th, mth, and (m+1)th bit positions every nth code word are searched to see if a preamble or synchronization code word is present.

Abstract: A method and circuit for estimating true data from distorted digital data signals which may have become degraded due to noise, in which signals are clocked into a shift register at a frequency rate higher than the data rate, for example eight times the data rate. The n outputs of the shift register stages are coupled to respective inputs of a majority logic circuit which has (n+1) inputs. A latching circuit clocked in antiphase to the clocking of the shift register is coupled to an output of the majority logic circuit. The output of the latching circuit is fed back to the (n+1)th input of the majority logic circuit.