USB to Serial Adapter on Mac: Driver and Device Setup
macOS has never shipped with broad third party serial drivers, and Apple Silicon removed the last of the old kernel extensions. What used to work by default now needs the right chipset and the right driver.
Quick Answer
Use an adapter with a chipset that publishes current macOS drivers, ideally with signed drivers for Apple Silicon. After installing, the device appears as a path under dev beginning with tty, and terminal software connects to that path rather than to a COM number. Older unsigned drivers may need approval in Privacy and Security before they load.
Chipset Support on macOS
| Chipset family | Intel Macs | Apple Silicon | Notes |
|---|---|---|---|
| FTDI FT232 series | Yes | Yes, with current driver | Most predictable choice |
| Silicon Labs CP210x | Yes | Yes, with current driver | Often included by the operating system for some parts |
| Prolific PL2303 | Version dependent | Limited | Counterfeit chips are rejected |
| WCH CH340 or CH341 | Community drivers | Community drivers | Works but support varies |
Installing the Driver
- Download the driver from the chip maker rather than a marketplace listing.
- Install and allow the system extension in Privacy and Security if prompted.
- Connect the adapter.
- Confirm the device path appears in the dev listing.
- Connect your terminal software to that path.
Finding the Device Name
Terminal command
List the dev directory filtering for tty entries both before and after plugging the adapter in. The new entry is your device.
Typical names
Names include the chipset identifier, for example a usbserial prefix for FTDI parts or a Silicon Labs prefix for CP210x parts.
Stability
The name usually stays consistent for a given chipset, which makes scripting straightforward compared with numbered COM ports.
Common Obstacles
Driver blocked
Modern macOS requires explicit approval for third party system extensions. Check Privacy and Security after installation.
Nothing appears
Usually a charge only cable, a charging only port on a hub, or an unsupported chipset.
Port busy
Another application has the device open. Close terminal sessions before reconnecting.
Real-World Applications
- Console access to network equipment from a MacBook.
- Instrument communication in a lab using macOS workstations.
- Field engineering with a laptop that has no legacy ports.
- Automating serial data collection with scripts.
Related Guides
For Windows setup, read USB to COM port adapter. For driver troubleshooting, see USB serial adapter driver. For chipset guidance, start with USB serial adapter.
FAQ
Does any USB serial adapter work on Apple Silicon without a driver?
Some Silicon Labs parts are covered by the operating system. Most others need a current vendor driver.
Why is my adapter not listed?
The driver did not load, or the chipset is not supported on that macOS release.
What port name should I use in my terminal app?
Use the tty path that appears when the adapter is connected.
Is there a permission problem with serial access?
Usually not for user owned device paths, but scripts running as services may need attention.