EMB-2510 User's Manual52.3.2 COM3 Jumper(J3)J3:COM3 AS RS232 PORT COM2 AS RS485 PORTJ3 1-3 J3 3-5J3 2-4 J3 4-62.4 Interfaces DescriptionPlease read this manual carefully before installing any external connectors, in caseof any damage to the motherboard!2.4.1 Serial Ports(COM_DB,COM3_4)EMB_2510 motherboard provides 3x serial ports , COM3 support RS232/RS485 ;COM2/4 support RS232.J3