The Tool Desk
Outbyte PC Repair FREEClear out junk files and repair common Windows errorsFree Scan →Outbyte Driver Updater FREEFix the driver behind crashes, sound loss and screen glitchesFind Drivers →A virtual serial port is a serial communication endpoint that software can use through a COM-style interface, even when the computer has no built-in serial connector. The term describes several different setups: a software-created pair of ports, a USB-to-serial bridge, or a serial device presented to a virtual machine. To know what a particular port does, first identify what it connects to.
What “virtual serial port” means
“Virtual” refers to the endpoint presented to an operating system or application; it does not tell you whether the connection is entirely software-based or backed by physical hardware. A port may appear under a COM-style name, but the communication path behind it depends on how the port was created.
As an Amazon Associate I earn from qualifying purchases.
Microchip describes one hardware-backed case as a USB serial bridge between a host PC and a target device, which provides a virtual communications port to host software (Microchip: 3.1.1 Virtual COM Port). Other implementations connect two applications on one computer or give a guest operating system a serial device.
What’s actually slowing this PC down?
Pick the symptom - the matching free tool is one click away.
Three common kinds of virtual serial port
Software-created port pair
Virtual serial port software can create two linked COM-style endpoints, often using a virtual null-modem connection. One serial application opens one endpoint and another application opens the other; data written to one can be read from its counterpart. This lets applications exchange serial data on the same computer without a physical serial cable (Virtual Serial Port Kit: Product overview).
#1 Best Overall
- !!Please NOTE: this is MALE RS232 to DB9 SERIAL CABLE ,Not VGA!!!It is 9 pin, NOT 15 pin!! Look carefully of the Pin is match with your device. Before ordering , please confirm the interface gender is waht you need. After receiving ,please read user manual /instruction at first and download the Driver at first from FT232 Official website or Cisco website . Customer service always online.
- Wide range of applications: USB to RS232 DB9 male serial adapter can work with your Windows (10 / 8.1 / 8 / 7 / Vista / XP), MAC or Linux system and other platforms. USB adapter is designed to connect to serial devices, such as serial modem with DB9, ISDN terminal adapter, digital camera, label writer, palm computer, barcode scanner, PDA, cash register, CNC, PLC controller, tax printer, POS, bar code scanner, label printer, etc
- High quality: ftdi usb serial,the latest ftdi chip set ensures more reliable and faster operation. USB 2.0 to RS232 male DB9 console cable will support 1Mbps date transfer rate.
- Most convenient: rs232 to usb simple installation, plug and play, COM port creation, baud rate can be changed to the required settings. USB power supply - no external power supply required.
- Exquisite design: usb-to-serial,Gold Plated USB RS232 connector and PVC cable ensure high performance and extra durability. Powered by USB port, this USB to DB9 series RS232 adapter cable is designed to fit easily into your handbag.
The port names, supported signaling, and compatibility depend on the software creating the pair. This setup is for connecting applications, not for connecting a computer to an external serial device.
USB-to-serial bridge
A USB-to-serial adapter connects a computer to a device with a serial interface. The adapter and its driver present a COM-style port to applications on the computer, while the physical adapter carries communication to the target device (Microchip: 3.1.1 Virtual COM Port; Citrix: Serial ports).
Rank #2
- [ USB to RS-232 Serial Adapter ] : 5ft Cable Length - Easily connect legacy DB-9 serial devices to modern USB-equipped computers. Uses include industrial, lab, and point-of-sale applications.
- [ Easy Testing ] : Built-in signal tester features full LED indicators with dual-color display for quick and easy testing of RS-232 host-to-device connections.
- [ Wide Compatibility ] : Built with an FTDI Chipset. Works seamlessly with Windows 7, 8, 10, 11, Linux, and macOS 10.X, making it a highly versatile solution across platforms.
- [ Why Gearmo? ] : Your trusted partner based in the USA, providing advanced engineering, highly reliable and superior built products to handle the most demanding industries for over 10 years.
- [ Engineering Support ] : Need specs? Contact us for CAD files, mechanical drawings, or datasheets to support your integration or project needs.
Choose this kind when you need to communicate with external serial hardware. It is not needed for a software-only pair of virtual ports. Check that the adapter, driver, connector, and electrical signaling match the target device.
Virtual-machine serial device
Virtualization software can provide a serial device to a guest operating system. The guest sees a serial port, while the virtual machine connects it to a resource configured by the virtualization software. In Oracle VM VirtualBox 6.0, documented options include a host pipe or TCP endpoint, and an enabled guest port can appear as a standard 16550A-compatible UART. Those details are specific to VirtualBox 6.0; other products may offer different settings (Oracle VM VirtualBox 6.0 User Manual: 3.10. Serial Ports).
Rank #3
- Serial adapter allows a serial device to be connected to a USB computer
- Plug and play convenience:DB9 serial port is seen as a COM port by your computer, and is available for use by any program that accesses COM ports
- No need for an external power adapter:draws power directly from your computer via the USB connection
- DB9 serial port supports data transfer rates up to 230 Kbps:twice the speed of a standard built in serial port
- LED shows adapter status and data activity at a glance
Which kind do you need?
| Use case | Connection | Physical hardware | Where the port appears |
|---|---|---|---|
| Connect two serial applications on one computer | Linked software-created endpoints | Not required | In the host operating system or applications, depending on the port software |
| Connect a computer to an external serial device | USB-to-serial bridge and driver | USB adapter and serial connection required | As a COM-style port on the host, subject to driver support |
| Give a virtual machine serial connectivity | Guest serial device attached to a configured resource | Depends on the attachment | Inside the guest operating system |
For two local applications, look for software that creates a paired virtual COM port. For an external device, use a compatible USB-to-serial adapter and install its driver. For a guest operating system, configure the virtual machine’s serial device and its attachment. These options solve different connection problems and are not interchangeable.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Why a COM port may appear but still not work
A COM-style name alone does not guarantee that a port is connected to the device or application you expect. Check what created it, which side of the connection you opened, and whether the required driver and signaling are supported.
Rank #4
- √USB to 9-pin serial cable Product features: easy installation, no external power supply, and physical drive required
- √Applicable scope: This product can easily realize the conversion between the USB interface of the computer and the universal serial port, providing a fast channel for the computer without a serial port, and using this product is equivalent to turning the traditional serial port device into a plug-and-play USB device.
- √ Supports various models of MCU, MCU STC download, LED screen control card, MODEM, and ISDN terminal adapter communication is suitable for computers or notebooks with USB ports.
- √Application platform: Support USB1.0/1.1 specification, compatible with USB2.0 specification, support full-speed transfer mode 12MBPS, support Win98, 98SE, Me, 2000, XP, Mac OS8.6, vista, win7-32, 64-bit.
- √Installation Instructions: 1. Run the driver CH340.EXE file to install 2. Connect the USB serial cable to the USB interface of the computer, and automatically install the driver 3. After the installation is successful, the COM port appears in the device manager
- For a software-created pair: confirm both applications use opposite endpoints from the same pair and that the port software supports the required serial settings.
- For a USB adapter: check driver installation and confirm the adapter’s connector and electrical signaling suit the target device.
- For a virtual machine: confirm that the serial device is enabled for the guest and that its host-pipe, TCP, or other attachment is configured as intended.
- For board-specific UART behavior: check the board documentation for control-line requirements. Nordic’s nRF52840 DK documentation, for example, says terminal software must send DTR to configure the UART interface MCU pins (Nordic Semiconductor: nRF52840 DK Virtual serial port).
Visibility and behavior therefore depend on the implementation, driver, operating system, and connection target—not simply on whether the port is labeled “virtual.”
Recommended Free Tools
Quick Recap
Best Value
- Gold Plated USB 2.0 to RS232 Female DB9 Serial Cable connects serial DB9 (9 PIN) devices such as modems to standard computer USB ports, supporting up to 1Mbps data transfer rate. [ IMPORTANT NOTE ]: This USB to RS232 adapter features a female RS232 connector, NOT male — please confirm your device’s serial port type before purchase
- Adopted with latest Prolific PL2303 chipset, this USB to RS232 adapter supports Windows 11/10/8.1/8/7, Linux and Mac OS. Windows 11/10/8.1/8/7 is plug-and-play and will be automatically identified as COM port. Windows built-in drivers match most USB-to-serial chips; it will automatically download and install the matched driver under network environment. For offline Windows, Mac OS and most Linux systems, please download and install the official driver from CableCreation official website. Ubuntu Linux supports plug and play without driver installation
- Widely compatible with modems, ISDN terminal adapters, digital cameras, label writers, palm PCs, PDAs, cash registers, CNC, PLC controllers, tax printers, POS machines, barcode scanners, and other devices with standard DB9 serial ports. Please be noted this USB to RS232 female DB9 serial converter cable is NOT compatible with cutting plotter and SCM equipment. Kindly confirm your device interface and model before placing an order
- Features tinned copper conductor and triple shielding to ensure stable and high-quality data transmission. USB bus-powered design requires no external power adapter. If your computer cannot recognize the cable normally, please match it with a null modem adapter for normal use
- CableCreation provides 24-month warranty and lifetime professional customer service. This 6.6ft USB 2.0 to RS232 Female DB9 serial converter cable follows standard pin definition, suitable for the device requiring female RS232 interface. If you encounter any problems of driver installation or device compatibility, please contact our customer service at any time, and we will assist you within 24 hours
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
