How to add more COM ports to the system?


Modern computers and laptops are vastly superior to those manufactured in the past. Every new model offers faster performance or more storage capacity to address the user’s computing requirements. In most cases, a new computer will serve you better than an older machine.

One area where a recently purchased computer is lacking, however, is in the number or availability of serial ports. Many manufacturers have eliminated COM ports totally in favor of the more popular USB interface. This can pose a problem for developers or system administrators who need to interact with serial devices and applications

Even if there is a COM port on your machine there may be times when you need to access several serial devices simultaneously. What can you do?

We are going to show you six methods of adding COM ports to a computer that does not have any or needs more for a specific purpose. One is a software solution and the others involve the addition of hardware to accomplish the goal.

Adding COM Ports to Your System

Here are six options for adding serial interfaces to your Windows system:

  1. Simulate COM ports with a software application
  2. Convert USB to COM port
  3. Convert Ethernet to COM
  4. Adding COM ports over WiFi
  5. Conversion or branching of RS-232, RS-422, RS-485
  6. Adding COM ports via PCI, PCIe, ISA buses

1. Simulate COM ports with a software application


We believe the most effective and efficient method of adding COM ports is through the use of special software. Creating virtual serial ports is a more flexible solution and eliminates the need for additional hardware or cabling.

Download VSPD to add an unlimited number of COM ports


Here are some of the Standard version’s outstanding features:


  • Provides the ability to create an unlimited number of virtual serial port pairs;
  • Fully emulates the settings of physical COM ports;
  • High-speed data transfer through the virtual ports;
  • Virtual null-modem schemes;
  • Automatic re-creation of virtual ports on reboot;
  • Windows kernel driver technology support.

The Pro version offers extended capabilities including:


  • Splitting and merging physical or virtual serial ports;
  • Setting individual read and write permissions for each port;
  • Sharing a physical serial interface with multiple applications simultaneously.

VSPD is a reliable and convenient solution to the problem of adding serial ports to your Windows computer. There is no extra equipment involved and it does not require you to use another of your system’s hardware interfaces.

2. Convert USB to COM port:


If your system has a free USB port, you can use it to convert between USB and serial signals.

The USB to serial adapter is a small piece of equipment that has a USB connector at one end and at least one, and perhaps multiple, serial connectors on the other end.

USB to Serial adapter

Belkin USB to COM port converter


There are 3 simple steps to launch USB to serial adapter:


  1. Download and install the driver for your particular converter.
  2. Plug the converter into the computer’s USB port.
  3. Attach a serial device to the converter.

Now you can interact with the serial device despite not having a physical COM port on your computer. This method requires that your computer has a free USB port.

3. Convert Ethernet to COM:


You can obtain an Ethernet to COM converter, also called a device server, that enables you to convert serial signals. The signals are sent over the network and your computer interacts with the devices through a virtual COM port.

Ethernet to serial device server

Ethernet to Serial device server with 4 RS-232/422/485


How to convert Ethernet port to COM port?


Using an Ethernet to COM converter entails these steps:

  1. Attach the serial device to the device server.
  2. Connect the device server to the Ethernet.
  3. Use your computer to communicate with the serial device through the Ethernet.

4. Adding COM ports over WiFi


Taking advantage of your computer’s WiFi capabilities is another way to add a COM port to your system. The concept is similar to the Ethernet converter except it uses your wireless network. Serial WiFi adapter allows connecting a COM port (RS232) device to secure or open wireless network or access point.

Serial to WiFi Adapter

Serial WiFi Adapter - RS232


Implementation involves:


  1. Connecting a serial device to the wireless device server;
  2. Broadcasting the signal on the WiFi network;
  3. Accessing the serial device on the WiFi network using your computer.

5. Conversion or branching of RS-232, RS-422, RS-485 interfaces


Perhaps you have an open COM port on your computer but need multiple interfaces for a specific purpose. You may also have a port that does not support the communication protocol of the device you intend to use. Both of these issues can be solved with the addition of some hardware and cables.

In the case of requiring more COM ports when you have one open on your machine, a Serial Port Hub is the solution. The hub will have one connector that attaches to the free serial port on your computer and several COM ports available to be used by devices. The devices essentially share your computer’s single port.

Serial port hubs - RS232 Serial Splitter

DTECH Industrial 8 Port RS232 Serial Splitter Switch


Converting between serial protocols such as RS232 to RS485 is also possible with a hardware converter. One end plugs into your machine’s COM port and the other connects to the serial device.

6. Adding COM ports via PCI, PCIe,
ISA buses


If your computer has expansion slots, they can be used to provide serial ports to the machine. Multiport serial card installs in slots in a PC on the ISA or PCI buses.

Many different serial expansion serial boards are available which provide multiple COM ports. They can support any of the serial communication protocols, and add functionality to your computer. Quite often, you may encounter a problem with a lack of free space for serial port connectors on the external-facing part of the card. To solve this problem, you just need to have a cable with connectors on both ends.

Serial port hubs - RS232 Serial Splitter

4 Port RS232 PCI Express Serial Card w/ Breakout Cable


Make sure that the card you obtain is for the type of expansion slot in which you plan to employ it.

To use one, follow these steps:


  1. Locate a free expansion slot on your computer.
  2. Open up the slot.
  3. Insert the card making sure it is properly connected to the computer.
  4. Install the card’s driver if necessary.
  5. Plug your serial devices into your newly obtained COM ports.

As you can see, there are a variety of ways in which you can add CM ports to your computer. Many of them require you to use additional hardware and cables. You may also be faced with the prospect of swapping devices in and out of your converters.

The more elegant solution is to use Virtual Serial Port Driver to create as many virtual serial ports as you need. It is a versatile serial communication application that enables any computer to interact with serial devices.

Virtual Serial Port Driver

Requirements: Windows (32-bit and 64-bit): XP(only Standard)/2003(only Standard)/2008/ Vista/7/8/10, Windows Server 2012, Windows Server 2016 , 5.5MB size
Version 9.0.575 (23rd May, 2019) Release notes
Category: Communication Application