Accessories for BL20 and BL67. RS232 Adapter Cable for the BL67/BL20 Service Interface. Ident. no.: 6827133. RS232 adapter cable. For BL67 service port (PS2). For connection of the engineering software I/O-ASSISTANT. For commissioning support. For system diagnostics. 9-pin SUB-D connector. PS2 connector. Cable length: 2.5 m