System for reading bar code symbols using bar code readers having RF signal transmission links with base stations

A system for reading code symbols comprising:

• (A) a plurality of code symbol reading devices, each said code symbol reading device including
• a scanning mechanism for automatically scanning a code symbol on an object,
• a processing mechanism for producing symbol character data in a form representative of the scanned code symbol,
• a synthesizing mechanism for synthesizing a group of data packets, each having a plurality of data fields containing codes for identifying the code symbol reading device synthesizing the data packet in the group thereof, a data packet number for identifying each said data packet, a data packet group number for identifying the group to which each said data packet belongs, and a sequence of digital data bits representative of the symbol character data, and
• an RF signal generator for generating an electromagnetic signal having its frequency modulated by the digital data bits representative of said group of data packets, and transmitting said modulated signal over a predetermined data transmission range in free space,
• wherein a frequency deviation of the signal produced by each said code symbol reading device is substantially the same and equal to a preselected frequency deviation value;
• and
• (B) a plurality of base units, each said base unit being assigned to one said code symbol reading device, and positionable within the predetermined transmitting range thereof, and including
• a receiver for receiving a modulated carrier signal transmitted from said any one of the code symbol reading devices,
• a demodulator for demodulating any one of the received modulated carrier signals so as to recover at least one data packet therefrom,
• a processing mechanism for analyzing the recovered data packet to determine whether the received data packet was synthesized by its assigned code symbol reading device, and if so, then recovering the symbol character data therefrom,
• a buffer for buffering the symbol character data recovered from the data packet synthesized by the preassigned code symbol reading device, and
• a notification mechanism for automatically producing, in response to the recovery and buffering of the symbol character data, an acknowledgement signal perceptible to a user of the assigned code symbol reading device when the user is situated within the predetermined data transmission range, so as to inform the user of the code symbol reading device that the symbol character data produced thereby has been received and recovered at the assigned base unit.