Pololu USB-to-Serial Adapter

SKU: POLOLU-391 Brand: Pololu

Retired Product

Search for an alternative
This product has been retired. It is no longer available, but this page has been kept for reference.

Note: This product is not recommended for new designs (NRND) based on Silicon Labs designating the CP2102 as NRND. Please see the CP2102N USB-to-Serial Adapter Carrier for a similar, newer adapter with a USB Micro-B connector.

The Pololu USB-to-serial adapter is great for connecting microcontroller projects to a personal computer. The adapter uses 3.3 V signal levels so you can connect it directly to any microcontroller running at up to 5 V without the hassle of an RS-232-to-TTL level converter. The tiny unit is only 1.0" x 0.65" including its mini-B connector, and the simple layout of the ground, transmit, and receive lines allows for easy mounting that takes up as little as four breadboard rows.

The USB adapter’s drivers make it look like a standard serial port to the operating system, allowing you to connect to all of your existing software, such as servo controller interface programs, through a USB port. The adapter is compatible with USB 2.0 standards and allows baud rates of up to 921.6 kbps. Drivers are available for Windows XP, Windows Vista, Windows 7, Windows 8, Windows 10, Linux, and Mac OS X.

With the trend toward removing serial ports from new computers, the Pololu USB-to-serial adapter provides one of the most economical, small, and simple solutions to the common problem of interfacing small projects to PCs.

Note: This product does not include printed documentation or software discs. The Pololu USB-to-serial adapter requires software drivers to operate; please see the resources tab for more information. This product requires a USB A to mini-B cable (not included) to connect to a computer.

Device specifications

  • PCB size: 1.0" x 0.65" including connector
  • USB standard: USB 2.0 (full speed)
  • Connector: USB mini-B
  • Data I/O voltage levels: 3.3 V (5 V tolerant)
  • Maximum data rate: 921.6 kbps
  • Supply current: 25 mA

Module pinout

Pin Type Function
DCD In "Data carrier detect" control input (active low)
DTR Out "Data terminal ready" control output (active low)(often used with DSR)
DSR In "Data set ready" control input (active low)(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)
GND Power Ground
TX Out Asynchronous serial data transmit (idle high)
VBUS Power USB bus voltage (+5V)
RX In Asynchronous serial data receive
SUSPEND  Out Driven high when in USB suspend state
SUSPEND  Out Driven low when in USB suspend state
RST In Device reset
RI In "Ring indicator" control input (active low)
VDD Power  3.3 V voltage regulator output

Typical connection

To connect a serial device to your computer’s USB port, you will most likely only need to use the GND, TX, and RX lines. The TX and RX lines use 3.3-volt levels, but the USB adapter input lines will tolerate up to 5.5 volts. Therefore, a direct connection to a microcontroller’s I/O lines is usually possible.

For some programs, it will be necessary to connect the handshaking lines (RTS, CTS, etc.) if the software does not establish a connection without those lines. In general, the handshaking lines can be left disconnected, used for their intended purpose, or used as additional I/O lines to the computer.

Documentation and other information

This product is listed in:

Retired

Product Comments

Exact shipping can be calculated on the view cart page (no login required).

Products that weigh more than 0.5 KG may cost more than what's shown (for example, test equipment, machines, >500mL liquids, etc).

We deliver Australia-wide with these options (depends on the final destination - you can get a quote on the view cart page):

  • $3+ for Stamped Mail (typically 10+ business days, not tracked, only available on selected small items)
  • $6+ for Standard Post (typically 6+ business days, tracked)
  • $10+ for Express Post (typically 2+ business days, tracked)
  • Pickup - Free! Only available to customers who live in the Newcastle region (must order online and only pickup after we email to notify you the order is ready). Orders placed after 2PM may not be ready until the following business day.

Non-metro addresses in WA, NT, SA & TAS can take 2+ days in addition to the above information.

Some batteries (such as LiPo) can't be shipped by Air. During checkout, Express Post and International Methods will not be an option if you have that type of battery in your shopping cart.

International Orders - the following rates are for New Zealand and will vary for other countries:

  • $11+ for Pack and Track (3+ days, tracked)
  • $16+ for Express International (2-5 days, tracked)

If you order lots of gear, the postage amount will increase based on the weight of your order.

Our physical address (here's a PDF which includes other key business details):

Unit 18, 132 Garden Grove Parade
Adamstown
NSW, 2289
Australia

Take a look at our customer service page if you have other questions such as "do we do purchase orders" (yes!) or "are prices GST inclusive" (yes they are!). We're here to help - get in touch with us to talk shop.

Have a product question? We're here to help!

Write Your Own Review

Guides

The Maker Revolution

The Maker Revolution celebrates the creation of new devices and the modification of existing ones - ...
The Maker Revolution celebrates the creation of new devices and the modification of existing ones - ...

Projects

Raspberry Pi Video Looper Display Installation | Overshare Video Festival

IntroductionA suspended ceiling display of forty repurposed screens and displays, each screening cr...
IntroductionA suspended ceiling display of forty repurposed screens and displays, each screening cr...

Mailbox Delivery Notification System

Introduction During the Covid lockdown, I needed something to do. The Postman or woman does not de...
Introduction During the Covid lockdown, I needed something to do. The Postman or woman does not de...

PiicoDev Schematic System

Introduction: Hi everybody. Over the past few weeks, I have been working on an intuitive system th...
Introduction: Hi everybody. Over the past few weeks, I have been working on an intuitive system th...
Feedback

Please continue if you would like to leave feedback for any of these topics:

  • Website features/issues
  • Content errors/improvements
  • Missing products/categories
  • Product assignments to categories
  • Search results relevance

For all other inquiries (orders status, stock levels, etc), please contact our support team for quick assistance.

Note: click continue and a draft email will be opened to edit. If you don't have an email client on your device, then send a message via the chat icon on the bottom left of our website.

Makers love reviews as much as you do, please follow this link to review the products you have purchased.