This item is the partial kit version of the 23201a serial adapter. All surface-mount components are assembled; the 12-pin header and DB9 connector are included but not soldered.
Dec 8, 2011 Update: We are now shipping a new revision of this serial adapter featuring a built-in power capacitor that makes this part less susceptible to damage from destructive LC voltage spikes. These new revisions are more robust drop-in replacements for the previous adapter version (they have the same dimensions, pin-out, and functionality).
![]() |
If you want to access all of the features on your computer’s serial port, this serial adapter is for you. The adapter allows you to connect your 3-5.5 V logic circuits to a COM port, which operates on higher and negative voltages (EIA-232, similar to the older RS-232 standard). The adapter is available fully assembled with male header pins facing down for use with prototyping boards and breadboards, or as a partial kit as shown to the right. The partial kit offers more flexibility if you do not need all of the header pins or if you want to install them on the other side of the board (or not at all).
This adapter distinguishes itself from most competing units through its five drivers and three receivers, which give you access to all eight signal lines on a DB9 connector (the ninth pin is ground). This means that in addition to standard serial communication, your project can also use all of the handshaking lines and status lines. Even if you do not use them for their intended purposes, you might find it convenient to be able to reset your processor using one of the extra lines. A connection detection line gives your project additional options for responding to a physical connection to a serial port. All of this connectivity comes in a compact package that is less than twice the size of the DB9 connector alone.
The first nine pins on the deluxe serial adapter correspond to the same nine pins on a COM port DB9 connector. The additional pins are the logic supply voltage, the serial connection detection pin, and an inverted version of the transmit line (which can be useful if, for instance, you have a positive-edge triggered interrupt that you want to fire in response to the beginning of the start bit). The TX line and RX lines are labeled from the computer’s perspective, so the TX pin has data transmitted by the computer that should be connected to your project’s receive input.
![]() |
| Pin | Type | Function |
|---|---|---|
| DCD | In | "Data carrier detect" |
| RX | In | Asynchronous serial data receive |
| TX | Out | Asynchronous serial data transmit (idle high) |
| DTR | Out | "Data terminal ready" control output (often used with DSR) |
| GND | Power | Ground |
| DSR | In | "Data set ready" control input (often used with DTR) |
| RTS | Out | "Ready to send" control output (often used with CTS) |
| CTS | In | "Clear to send" control input (often used with RTS) |
| RI | In | "Ring indicator" control input |
| VCC | Power | Logic supply voltage (3 – 5.5 V, externally supplied) |
| INV | Out | Serial port detection pin, high if serial port connected |
| TX | Out | Asynchronous serial data transmit, inverted (idle low) |
![]() |
Pololu USB-to-Serial Adapter |
![]() |
Pololu 23201a Serial Adapter Fully Assembled |
Manufacturer BTC Korporacja sp. z o. o. Lwowska 5 05-120 Legionowo Poland sprzedaz@kamami.pl 22 767 36 20
Responsible person BTC Korporacja sp. z o. o. Lwowska 5 05-120 Legionowo Poland sprzedaz@kamami.pl 22 767 36 20
USB-UART TTL converter based on the CH343G chip. Equipped with a number of security features ensuring stable and safe communication. Waveshare CH343 USB UART Board (type C)
USB - UART converter based on the PL2303TA chip. Compatible with voltages of 3.3 V and 5 V, it has been equipped with a miniUSB connector. Waveshare PL2303 USB UART Board (mini) V2
No product available!
KAmod RS232S-ALL is a 3-5.5V RS232 to TTL converter supporting all RS232 signals, offering standard DB9 and Phoenix MC 3.81 connectors and 2.54mm goldpins, based on the MAX3238/SP3238 and providing ESD protection up to 15kV
RS232 - UART converter module based on the MAX3232 chip. There is a DB9 connector on the board and a 4-pin connector with a 2.54 mm pitch
The FT232RNL USB to UART converter provides stable serial communication and debugging of industrial equipment, supporting 3.3V and 5V voltages and hardware flow control. With power indicators, protection diodes, and compatibility with multiple operating systems, it offers reliable data transfers from 300 bps to 3 Mbps, as well as additional protections against faults and electrostatic discharge. Waveshare USB TO TTL (C)
No product available!
USB-UART converter for Odroid minicomputers. It is based on the CP2102N chip and is equipped with a USB type C connector
USB - UART TTL converter based on the FT232RL chip, the module is equipped with a miniUSB socket. Works with 3.3V or 5V voltage levels.
The module allows you to send UART (TTL) bus signals to a computer via a USB port. The adapter operates based on the PL2303HX chip and is recognized in the computer as a virtual serial port
USB - UART converter based on the FT232RNL chip. Compatible with voltages of 3.3 V and 5 V, it has been equipped with a miniUSB connector. Waveshare FT232 USB UART Board (mini)
No product available!
The Adafruit CH9328 UART to HID Keyboard Breakout allows for easy and fast emulation of a HID keyboard without the need for a microcontroller with native USB. The module is used in prototyping projects, automation, integration with single-board computers and in testing devices where keyboard signals are required. Thanks to support for various transmission modes and simplicity of integration, it is a practical tool for electronics engineers and embedded system programmers. Adafruit 5973
No product available!
The module with the converter USB-UART CP2104 dedicated for minicomputers Raspberry Pi. Adafruit 3589
The module with the UART-RS232 converter is designed to work with the Raspberry Pi Pico. It has a built-in SP3232EEN chip and enables data transmission between the UART interface and the RS232 device. Waveshare Pico-2CH-RS232
USB to TTL Serial Cable - Debug / Console Cable for Raspberry Pi, RoHS
USB-UART TTL converter based on the CH343G chip. Equipped with a number of security features ensuring stable and safe communication. Waveshare CH343 USB UART Board (mini)
No product available!
Converter dedicated to industrial applications. It provides communication between the USB interface and the RS232 and RS485 serial standard
UART - RS232 converter with DB9 socket. Waveshare rs232-board