It’s a numeric only bar code. Due to the interleaving of the characters, the number of characters in an Interleaved 2 of 5 message must be even. The check character, if used, must be included in the character count Especially adapted to the poor quality of packaging materials frequently used for trade items (corrugated cardboard), it is designed to be read by a fixed or portable bi-directional scanner.It’s a numeric only bar code. Due to the interleaving of the characters, the number of characters in an Interleaved 2 of 5 message must be even. The check character, if used, must be included in the character count Especially adapted to the poor quality of packaging materials frequently used for trade items (corrugated cardboard), it is designed to be read by a fixed or portable bi-directional scanner.