How to Share a Keyboard and Mouse Between Multiple Computers Without a KVM

Photo by Paul Healey

If you're someone who works in media, graphics, IT, or maybe you're just a stock market trader--chances are you have multiple computers in close vicinity running multiple applications. In that kind of situation it pays to be able to use the same peripherals for each machine to speed up workflow, save time and save space. To solve this problem, a person would traditionally use a KVM (Keyboard Video Mouse), which is a piece of hardware that allows you to share a single monitor, keyboard and mouse among all of the machines. But in that scenario you can technically only see and work on one machine at a time. What if, instead, you have multiple machines, each with its own monitor--and you need to be able to use the same keyboard and mouse with all the machines at once--instead of just flipping through one machine at a time? Now thanks to a free, open source application from Sourceforge called "Synergy," you do this all in software without a KVM. Using Synergy you can move a single mouse cursor from the screen of one computer to the screen of another computer just by crossing the edge of the screen, and also thereby share the same keyboard and clipboard among those machines. Here is how it's done.

Things You'll Need

• Network (Wireless or Wired)
• Synergy Software (See Resources Section)
• A Keyboard
• A Mouse
• A Monitor for each machine

Instructions

1. First of all, for Synergy to work you must have all of the computers on the same network. Each computer should have its own monitor. The monitors can be set up side by side or above and below each other.

2. 

   Download Synergy (see link in Resources below). These instructions are for Windows, but Synergy can also be used for Macs and Linux machines. You can even share a keyboard and mouse between machines that have different operating systems. You need to download the Synergy .exe or binary to each machine that you want to use.

3. 

   Start by running the SynergyInstaller exe that you downloaded on the server first. The computer that has the keyboard and mouse that you want to use is going to be the "server." Choose "Share this computer's keyboard and mouse (server)" and then click Configure.

4. 

   Now we will tell the server what computers you have. In this example I have two computers, a client on the left and the server on the right. Their monitors are side by side respectively. Hit the plus sign under "Screens" and enter a screen name for the server. In this example the server is called "VAIO." Repeat this process and add the screen name for the client, which in this example is "Pavilion." The screen names can be whatever you want, but by default Synergy wants to use your computer's current hostname. If you do decide to use a name different than the hostname, you will need to click the Advanced button and tell Synergy what the computer's screen name will be.

5. 

   Here comes the more complex part where you will actually tell the server software how you want it to handle the monitors. For this example, you need to tell the software that the client monitor is on the left and the server monitor is on the right. To do that hit the plus sign under "Links" and enter:

   "0 to 100% of the right of Pavilion goes to 0 to 100% of Vaio"

   Hit OK, and then repeat to add another link that says:

   "0 to 100% of the left of Vaio goes to 0 to 100% of Pavilion"

   If you have more monitors, or if they are a different configuration, you can alter this to your liking. Click OK to save your settings, and then hit Start for the server to begin. You should see the Synergy icon appear on your lower right taskbar.

6. 

   Now it's time to set up your client. Run the SynergyInstaller exe on the client machine and choose "Use another computer's shared keyboard and mouse (client)." Enter the screen name of the server in the field marked "Other computer's Host Name." If you decide to use a different name than the hostname for the client, you will need to click the Advanced button and tell Synergy what the client computer's screen name will be. Once you're set up, click Start and the client will connect to the server.

7. Now you should be able to use the mouse on both computers. Once the mouse passes the left edge of the screen on the server it will enter from the right-hand edge of the screen on the client. You can also use the keyboard on whatever computer currently has the mouse cursor and copy the clipboard (text, print screens, etc.) from one computer to another.

   If it's not working for you, double-check to make sure the screen names are set up properly and that you have enough links set up. Good luck!

Resources

• Synergy at Sourceforge