There are two typical RS232 cables used in the industrial.
Cross cable wiring for RS232 usually happens between two DCE (data communication equipment) devices, or two DTE (Data Terminal Equipment) devices.
Reference pinout diagrams for DB9 connector (sometimes known as DE9 connector or D-sub connector) for RS232 serial communication ports. RS232 is a serial data communication signalling protocol. D-sub 9pins or 25pins connector is commonly use for RS232. These days RJ45 (or 8P8C) modular connector is also commonly used for RS232 purpose.
Note:
For 3 wires RS232 serial communication (non-hardware-handshaking or asynchronous data communication) wiring, you only need pin 2, 3 (RX, TX) and pin 5 (Gnd)
Typically the TX pin of a RS232 D-sub connector represent data flowing out of the connector, flowing into the RX pin of its mating connector. This is a communication channel between two devices.