When the NAPLPS standard is used, how does the sending computer indicate to the receiving computer that the data it is receiving are not standard ASCII data?

When the NAPLPS standard is used, how does the sending computer indicate to the receiving computer that the data it is receiving are not standard ASCII data : 

The NAPLPS standard  is designed so that the receiving computer  will constantly scan the incoming data for an escape (1BH). Upon receiving the escape value, the receiving computer will interpret the next value sent as an NAPLPS command.