USB to Serial Console Cable: USB Meets RS-232
Serial equipment outlived serial ports. This cable is the bridge, and its details decide whether it works first try.
Quick Answer
| Attribute | Detail |
|---|---|
| Function | USB host to RS-232 serial conversion |
| Chip | Mainstream chipsets install drivers automatically |
| Wiring | Straight or null modem, matching the equipment |
| Connector | DB9 on the equipment side |
| Settings | Per equipment, commonly 9600 baud 8N1 |
Straight Versus Null Modem
Straight cable
Connects a computer to a modem class device. Pin 2 to pin 2.
Null modem
Crosses transmit and receive between two DTE devices, like console ports and other computers.
Which you need
Equipment documentation states it. Wrong choice shows as no response, not an error.
Adapters
A null modem adapter converts a straight cable when needed.
Setup Checklist
- Connect and confirm the COM port appears.
- Set the equipment’s documented speed and framing.
- Choose the correct cable wiring for the equipment.
- Open the terminal and press enter.
- Swap to a null modem if there is no response.
Real-World Applications
- Console access to equipment with DB9 ports.
- Industrial devices with serial management.
- Legacy instrumentation and test equipment.
- Point of sale and kiosk maintenance.
Related Guides
For the console family, read console cable. For the RJ45 form, see USB console cable. For the switch use case, start with switch console cable.
FAQ
Why no response from the device?
Wrong wiring type, wrong COM settings, or a driver issue.
What is a null modem?
A wiring that crosses transmit and receive between two DTE devices.
Does the chip matter?
Yes. Mainstream chipsets avoid driver hunts.
What speed do I use?
Whatever the equipment documents. 9600 8N1 is the classic.