All USB to UART, RS232 Converters comes under this category.
CP2102 USB to UART Converter
The CP2102 USB to UART Converter Module provides a serial port for your computer, ie. a virtual COM port to connect to a serial device. The IC used CP2102 is stable and reliable. It supports baud rates from 300bps to 1.5Mbps and driver support for a wide range of Operating Systems.
FT232 USB to UART TTL converter
Convert USB to UART using of FT232 USB to UART TTL Converter. It can also be used to program ArduinoUNO ATMEGA 328 and directly use it circuits. Compatible with 3.3V and 5V UART TTL.
PL2303 USB To UART converter
PL2303 USB to UART converter is a popular tool used for sending and receiving data from an UART interface through the usb port of a computer. This converter avoids the need of programming a micro-controller and enables to receive and send data between uart modules like GSM, GPS, Bluetooth, Wi-Fi etc and a computer having a USB port. This converter is manufactured by Prolific Technology Inc.