Horner Automation · Legacy Series 90-30 Communication HE693SNP232A SNP to RS-232 Adapter The HE693SNP232A is an RS-232 to RS-422 converter identified by Horner for use with the Series 90-30 PLC serial port for SNP communication. Product Overview Interface Role Horner identifies the HE693SNP232A as an RS-232 to RS-422 conversion interface for Series 90-30 PLC serial communication. It is used where an RS-232 interface needs to communicate through the PLC's RS-422 serial