other conventional techniques such as setting a bit flag for each address in the symbol matrix when it is filled a character could also be determined to be 34 new 34 if its assigned address were already occupied but the value of the newly decoded and previously decoded characters differed if the newly decoded character is determined to be new then charcount is incremented at step 335 otherwise it is not incremented another approach to setting the value of charcount during decoding is the following 2 assigning a second value to each character that was previously recognized in a preceding scan of the indicia 3 cumulating the first value into a first sum and cumulating the second value into a second sum 4 computing a function of the first sum and the second sum and the value of charcount is tested at step 337 if the value of charcount is at least 50 then on off signal 532 is asserted by the microcomputer 30 enabling an annunciator 530 to emit a short click at step 340 charcount is decremented by 50 at step 345 as in the case of the preceding embodiment the constant 50 should be understood to be representative and it can be varied without departing from the spirit of the invention after decrementing charcount or in the event that the test at step 337 was.