USB-to-Serial Adapters: FTDI vs Prolific vs CH340 Chipsets
Modern computers rarely include traditional serial ports, but RS232 and other serial connections are still widely used in industrial equipment, networking hardware, point-of-sale systems, control equipment, test instruments, and legacy devices.
A USB-to-serial adapter lets newer computers communicate with this equipment through USB. When shopping for one, you will often see chipset names such as FTDI, Prolific, and CH340. These chipsets perform the USB-to-serial conversion, but the right adapter also depends on the serial standard, connector type, USB connection, drivers, and the equipment you need to connect.
PCCables.com carries USB-to-serial solutions using FTDI, Prolific, CH340, and other controllers, along with traditional serial cables and adapters.
Picture: Group photo of several PCCables.com USB-to-serial adapters showing DB9, USB-A, USB-C, and RJ45 styles.
What Is a USB-to-Serial Adapter?
A USB-to-serial adapter converts a computer's USB connection into a serial interface that older or specialized equipment can use.
The most common example is a USB-to-DB9 RS232 adapter, but USB can also be converted to RS422, RS485, TTL serial, and RJ45 serial console connections.
For many RS232 applications, the adapter appears to the computer as a COM port. Software can then communicate with the connected equipment much like it would with a traditional built-in serial port.
Our popular 3FT DB9 RS232 Serial to USB Adapter
Why Does the USB-to-Serial Chipset Matter?
The chipset inside the adapter handles communication between USB and the serial interface. It also determines which manufacturer's drivers are used.
FTDI, Prolific, and CH340 all accomplish similar USB-to-serial tasks, but they use different hardware and driver families. Some industrial devices, applications, or manufacturers may recommend a specific chipset.
The chipset should not be the only factor in your decision. You also need to make sure the adapter supports the correct serial standard, such as RS232 or RS485, uses the right connector, and matches either USB-A or USB-C on your computer.
FTDI USB-to-Serial Adapters
FTDI is one of the best-known manufacturers of USB interface controllers. Compatible FTDI devices can use Virtual COM Port drivers that allow the adapter to appear as another serial COM port on the computer.
PCCables.com offers FTDI USB-to-DB9 adapters in both USB-A and USB-C versions. USB-A options are available in 1 ft, 3 ft, and 6 ft lengths, with matching USB-C versions in 1 ft, 3 ft, and 6 ft.
USB-A to DB9 and USB-C to DB9 3FT FTDI Adapters
FTDI-based adapters are not limited to RS232. PCCables.com also carries FTDI products for RS422, RS485, TTL serial, and RJ45 console connections.
For example, our USB to DB9-Male RS422-RS485 FTDI Adapter converts USB to a DB9 connection supporting RS422 and RS485. Note that connectors alone do not determine compatibility, and although DB9 RS232 and a DB9 RS485 adapters may look similar physically, they support very different electrical interfaces.
Prolific USB-to-Serial Adapters
Prolific is another common manufacturer of USB-to-serial controllers. Its PL2303 family is widely used in USB-to-RS232 adapters.
PCCables.com carries Prolific-based USB-to-DB9 adapters in both USB-A and USB-C versions. Like our FTDI cables, USB-A models are available in 1 ft, 3 ft, and 6 ft lengths, with matching USB-C options in 1 ft, 3 ft, and 6 ft.
A USB-C version can be particularly useful with newer laptops and compact PCs that no longer have traditional USB-A ports, allowing connection directly from USB-C to a DB9 serial device. These USB-C Prolific adapters enable newer laptops and compact PCs to connect to DB9 serial equipment used in industrial, POS, networking, and instrumentation applications.
USB-A to DB9 and USB-C to DB9 1FT Prolific Adapters
Browse our entire Prolific selection here on our website!
CH340 USB-to-Serial Adapters
CH340 is a USB conversion chipset manufactured by WCH. It is commonly found in USB-to-serial cables, adapters, development hardware, and console cables.
One example from PCCables.com is the USB to RJ45 Cisco Router Console Serial Cable, which uses a CH340 controller.
Unlike a typical USB-to-DB9 adapter, this product connects USB directly to an RJ45 serial console port used on compatible networking equipment.
This demonstrates an important point: USB-to-serial does not always mean USB-to-DB9.
USB-to-DB9 vs USB-to-RJ45
USB-to-DB9 adapters are commonly used with industrial controllers, test equipment, POS systems, modems, legacy peripherals, and other RS232 devices.
USB-to-RJ45 console cables serve a different purpose. They are commonly used to configure routers, switches, and other networking equipment through a serial console connection.
Although the RJ45 connector looks like an Ethernet connector, an RJ45 serial console port is not the same as an Ethernet network connection. The connector may be physically similar, but the electrical signals and pinout are different.
Connector close-ups from a 6FT USB-C to RJ45 FTDI Cable
RJ45 serial connections are not limited to USB console cables. PCCables.com also carries modular RJ45 adapters for DB9, DB15, and DB25 connections, including male and female configurations. These adapters are useful for serial devices, console connections, telecom equipment, and custom wiring applications where an RJ45 cable needs to connect to a D-sub interface.
See our complete RJ45 selection here!
FTDI vs Prolific vs CH340
| Chipset | Example Connection | Common Application |
|---|---|---|
| FTDI | USB to DB9 RS232 | General and industrial serial equipment |
| FTDI | USB to DB9 RS422/RS485 | Industrial control equipment |
| Prolific | USB-A to DB9 | RS232 equipment |
| Prolific | USB-C to DB9 | Serial equipment with newer computers |
| CH340 | USB to RJ45 | Router and network console connections |
There is no single chipset that is automatically the best choice for every application. If the manufacturer of your equipment specifies FTDI, Prolific, CH340, or another controller, that recommendation should carry significant weight.
Otherwise, start by matching the serial standard and connector to your equipment.
Frequently Asked Questions
Is FTDI better than Prolific?
Not universally. Both are established USB-to-serial controller families. The better choice depends on your equipment, software, drivers, and any chipset requirements specified by the manufacturer.
Is CH340 the same as FTDI?
No. CH340 and FTDI are different USB-to-serial controller families produced by different manufacturers.
Can I use a USB-to-serial adapter with a DB9 device?
Yes, as long as the adapter supports the same serial standard and pinout as the equipment. A matching DB9 connector alone does not guarantee compatibility.
Can I connect RS485 equipment through USB?
Yes. You need a USB adapter specifically designed for RS485 or RS422/RS485 rather than a standard RS232 adapter.
Can I add a serial port to a USB-C computer?
Yes. USB-C-to-DB9 serial adapters allow newer computers to connect directly to compatible serial equipment.
Find USB-to-Serial Adapters at PCCables.com
Serial communication may be decades old, but it remains important for industrial controls, networking equipment, instrumentation, POS systems, and legacy hardware.
PCCables.com offers FTDI, Prolific, and CH340 USB-to-serial solutions for USB-A, USB-C, DB9, RS232, RS422/RS485, TTL, and RJ45 console applications.
When choosing an adapter, focus first on the serial standard, connector type, USB connection, and driver requirements. Once those are known, choosing the appropriate FTDI, Prolific, CH340, or other USB-to-serial adapter becomes much easier.
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