Vending machine communication link transmitter which handles packet fragments rather than whole packets to minimise buffer size

摘要

It is useful for vending machines to be able to communicate status information (eg faults, stock levels, etc.) to maintenance teams over either wired or wireless networks. However the processing capabilities of the vending machines may be limited. Information packets may be sent to a network transmitter over an internal bus (eg a DEX (Data EXchange) bus), and this may involve fragmentation of the packets into blocks small enough to be handled by the bus. Prior art transmitters would await all of the blocks (0-2) before processing them to produce an RF telegram (Pc) to send to an RF receiver for onward transmission over an RS 232 network (Pd). The disclosed transmitter processes each fragment/block separately (Bc) and will not accept the input of a new block until the current one has been dealt with. Thereby the transmitter can utilise a smaller buffer.