DB25 pinout guide. Since the introduction of the smaller serial port on the IBM-AT, 9 pins RS232 connectors are commonly used. RS 232 Pinouts for DB25 and DB9 Connectors Last updated; Save as PDF Pins commonly used for RS-232 (serial): Commonly used RS232 Null Modem Pin out for DB25 and DB 9 connectors: RS232 DB25 pinout RS232 DB25 to DB9 converter The original pinout for RS232 was developed for a 25 pins sub D connector. 3ft DB25 M/M Serial RS232 Cable Connect your printer, modem or other RS-232 serial/parallel device to a switchbox RS232 port (DB25 serial port). Wiring, pinout and signals for full RS232 connector In stock and ready to ship. In mixed applications, a 9 to 25 pins converter can be used to connect connectors of different sizes. Choose from our selection of DB25 connectors, including computer connectors, computer adapters, and more. Many audio interfaces, AD/DA converters, digital mixers, and other devices use DB25 connectors to carry eight channels of AES/EBU.Typically these cables “break out” into XLR connectors (four male connectors, four female connectors) to accommodate individual stereo AES/EBU connections.