The NS-series Programmable Terminal Is Not Equipped With An RS-422A Port, So How Can It Communicate Beyond The Rated Distance For RS-232C (15 m)?

Use an NS-AL002 RS-422/RS-232C Converter.

Just attach the NS-AL002 Converter to the RS-232C connector to use it as an RS-422A port. Use an NT-AL001 RS-232C/RS-422A Link Adapter to convert serial communications at the Programmable Controller.