Data collecting and transmitting system

摘要

A data collecting and transmitting system includes a dynamic MOS circulating memory in a portable hand-held unit. The memory is divided into N discrete time slots in a repetitive time frame for storing N data entries supplied by a keyboard input or a peripheral input unit. A load point counter operating in the same time frame is slipped a time slot on each entry to provide a variable marker representing the next empty time slot for receiving an entry. The memory contents can be supplied to a visual display in the hand unit or to an external transmitter into which the hand unit can be plugged. An output point counter operating in the same time frame is slipped a time slot as each stored data entry is read out to provide a variable marker representing the next data entry to be withdrawn from storage. The system also includes a message counter whose contents are transferrable to the visual display to indicate the number of entries, and this system also includes a clock rate control for changing the time frame between a slow rate for circulation of data and a fast rate for input and output operations. The hand unit is normally powered by batteries but operates on a line power source when plugged into the transmitter to permit the hand unit batteries to be charged during the transmission period.