It is intended to block non-ASCII characters. IPC-356 is a punched-card style format (I'm not joking) and in fact it only handles upper case letters: I'm not sure but I think the 'safe' character set is 0-9A-Z plus _, + and -; MAYBE other characters are supported but I wouldn't count on it.
Since it's column based an encoding like UTF8 is not feasible, and, anyway, CAM350 chokes even with simple latin1 characters.
So, yes, I did it for a purpose! There is a 356B around but nobody uses it (even 356A is not widely accepted)
It is intended to block non-ASCII characters. IPC-356 is a punched-card style format (I'm not joking) and in fact it only handles upper case letters: I'm not sure but I think the 'safe' character set is 0-9A-Z plus _, + and -; MAYBE other characters are supported but I wouldn't count on it.
Since it's column based an encoding like UTF8 is not feasible, and, anyway, CAM350 chokes even with simple latin1 characters.
So, yes, I did it for a purpose! There is a 356B around but nobody uses it (even 356A is not widely accepted)