Support RS232 serial interface (both DB25 and DB9). The USB to Serial/Parallel Adapter provides the connection between USB and the traditional RS-232 serial port. Since the adapter uses no IRQs, it is perfect if you need many serial devices attached to your PC.
eBay
FTDI USB RS232 Serial Converter Module USB Plug Adapter Board FTDI USB PCB Serial Converter Module Connector Support Win10
Aliexpress UK
Allow you to connects a PC without serial port to a serial device as it adds a DB9 port to a laptop or desktop via USB port. 1 x Db9 female to usb 2.0 female cable. 90° Angled USB 2.0 Type A Male to Female Extension Cable Cord Connector.
eBay
WiFi Antenna 2.4GHz/5.8GHz Dual Band 6DBi RP-SMA Connector for Mini PCI Card Camera USB Adapter Wireless Network Router
Aliexpress UK
USB C to DB9. Available in 1 or 2m lengths. Supports RS-232 Serial Interface.
eBay
Usb to Rs232 Serial Cable Female Port Switch USB to Serial DB9 Female Serial Cable USB to COM
Aliexpress UK
SKU: 010702 BRAND: NEWLink EAN: 5054338107028 WEIGHT: 0.093.
eBay
Usb to Rs232 Serial Cable Female Port Switch USB to Serial DB9 Female Serial Cable USB to COM 2M
Aliexpress UK
Plug Type: USB 2.0 to 9 Pin Male RS232. Interface: RS232. It allows you to use bridge or connectivity between the USB and serial port interface. Colour: Blue. Happy Buying.
eBay
TTL-232R-3V3 USB to TTL Serial Cable Adapter FTDI Chipset FT232 USB to 3.3v 5v TTL UART Serial RS232 Download Cable
Aliexpress UK
Features: Multifunctional switching: Realizes the quick connection between USB and RS232 serial port and facilitates data transmission. Transmission: supports fast data transmission, and is suitable for application scenario requiring high efficiency and stable transmission.
eBay
USB to RS232 RS485 RS422 TTL 4 in 1 Serial Converter with FTDI chip USB to RS232 Serial Cable USB to TTL USB to rs485 FT232RNL
Aliexpress UK
6ft industrial grade USB to RS232(DB25 Male) adapter cable. It is an ideal solution for computer to communicate with many serial devices directly through USB port such as CNC, PLC, plotter, modem, Scanner etc.
eBay
USB to RS232 Serial Port Adapter Connector 9-Pin DB9 Serial COM Port Adapter Converter Cable
Aliexpress UK
Support protocol: RS232. Type-c male to DB9pin male RS232 COM serial cable 1. Added a DB9PIN female-to-female adapter version, you can switch out of DB9pin male connector, and you can switch out of DB9pin female connector, allowing you to use one wire for two purposes.
eBay
New USB to RS232 COM Port Serial Port 9 Pin DB9 Cable Serial Adapter Convertor With Female Adapter Supports for Windows 8 No CD
Aliexpress UK