Frequently Asked Questions


Do I need to spend a lot of money on a tablet or laptop?

Since VMSpc does not require a lot of storage space or processing power, there are very few requirements. In shopping for a device, you will need to look for the following features:

  1. The operating system must be Windows, not Windows 10 S, which is configured to use only software from the App Store, hence the ‘S’. Windows 10 S can be reconfigured as a standard Windows installation, but it may be easier to simply find a device with Windows 10 Home or Windows 10 Professional.
  2. The device must have a full-size USB type-A port separate from the charging port.

Most folks prefer a 10 inch or larger screen so that gauges are easy to read. It does not need to have a CD Rom, since you can download the program from our website for free. The Microsoft Surface Pro has a unique issue specific to that product line–one outside our control. VMSpc rarely works on these devices as the driver requirements are unusual. Beyond this, it is difficult for us to recommend a specific device because the market changes so quickly. 


How do I install the drivers?

Drivers need to be installed before the JS500 (Serial) and JS501 (USB JIB) will communicate with the computer. Driver installation depends on which JIB hardware you own. For more help on which JIB you have, click here: Which JIB model do I have? 


If you use a USB JIB (JS501) download the latest drivers from here: VMSpc USB driver installation Run the app “Install Drivers.exe” then reboot. Use the latest version (from the website) for the easiest, pain-free, installation. 


If you have a Serial JIB (JS500) you only need drivers if you are using a USB to serial adapter to plug into your computer’s USB port. Click here for driver installation instructions for your USB to serial adapter: VMSpc Serial to USB adapter driver installation


How do I install VMSpc?

To install VMSpc on your computer follow these steps:

  1. Put the VMSpc disk into your computer or download the install files from our website: VMSpc Downloads. Note: the downloaded files will need to be unzipped (extracted) before using.
  2. Find the file VMSpc30_Install.exe and double click on it.
  3. The installation wizard should open. Follow the wizard’s instructions to install VMSpc. A seperate file “Install Drivers.exe” is also on the installation CD. Use it to install the needed drivers (then, reboot.)


Data is intermittent or drops out. What can I do to fix this?

If you are seeing engine data periodically drop to zero or only update sporadically, it could be an intermittent connection issue. Double check connections to make sure they are tight and that the wires are not slipping out of their crimps. If you own a JS501 JIB there are more specific instructions here: Data intermittent or drops out JS501. Not sure which JIB model you have? Check here: Which JIB model do I have?


How can I transfer my VMSpc to another computer without losing information?

VMSpc consists of the main program executable (VMSpc.exe) and a bunch of data files that includes trip, screen layout, and diagnostic information. These data files are what need to be retained in order to keep the same information. You can do this one of two ways. Either install a new version of VMSpc on the new computer and then copy the data files over from the old computer, or copy the entire VMSpc folder from your old computer to your new computer. If you do this last way you will probably want to create a shortcut to VMSpc.exe on your desktop (right-click on VMSpc.exe, Send to -> Desktop (create shortcut)). Important data files include:

  • odometer.dat
  • settings.dat
  • tires.dat – tire data
  • paramtrs.dat – parameter information
  • alarms.dat – audible alarm setup
  • diagnostics.txt – engine diagnostic code history
  • *.trp – trip files
  • *.scr – screen files
  • maintenance.vms – data for maintenance manager


I can’t get the program to install because Windows Defender says it’s malware.

Disable Defender. Download and install the software. Re-enable Windows defender.


I get no engine data. What should I do?

If you are not getting any engine information on VMSpc, first check the communication status. Click on Advanced -> Communications  You could see one of three possible errors:

  1. PC Port Failure – VMSpc can’t open the indicated port. For JIB Model JS500 click here: PC Port Failure JS500 For JIB Model JS501 click here: PC Port Failure JS501
  2. Failure Between JIB and PC – VMSpc opened the port, but cannot see data from the JIB. For JIB Model JS500 click here: Failure Between JIB and PC JS500
  3. For JIB Model JS501 click here: Failure Between JIB and PC JS501
  4. Failure Between Engine and JIB – VMSpc found the JIB, but the JIB is not getting data from the vehicle. Check diagnosis here: Failure Between Engine and JIB

Not sure which JIB model you have? Check here: Which JIB model do I have?


I just upgraded to Win-10 and now my gauges read ‘0’.

Your’ drivers were broken in the process of updating. No problem. Re-run the App “Install_Drivers” either from the disc or as a download from the website. Run this “As Administrator” to ensure Windows doesn’t stop the fun.


My VMSpc shows incorrect mileage or odometer information. How can I correct this?

Generally the data displayed by VMSpc is extremely accurate. But an improperly calibrated engine may send speed, distance, and fuel information that is consistently wrong. For example, if you put larger or smaller tires on the coach, the speed and odometer data will clearly be incorrect. To compensate for this kind of error you can enter correction values in the Engine Corrections dialog box. For the odometer, hourmeter, and fuelmeter you can enter both an “Offset” and a “Multiplier”. VMSpc will automatically add the Offset to the indicated meter, then Multiply the result by the multiplier. In addition, the multiplier will be applied as appropriate to the Speed, Cruise Speed, MPG, Fuel Rate, and Rolling MPG gauges. For example, if your engine was reprogrammed and lost its history at the 20,000 mile mark, and you added tires that cause it to understate the speed by 5%, change the Odometer Multiplier to 1.05. Change the Offset to 19,408. (Remember that the Offset is added, then the Multiplier is applied. 19,408 * 1.05 =20,000.)  

In the event that the VMSpc cannot parse the data correctly so as to overcome data bus errors (as is the case with some Cummins ISC and ISL engines) two solutions are in place: “The Check Boxes” (check them both to force more queries for data) and A simpler/ older VMS program to use in the place of v3.x. Here’s the link for Version 2.5x here from VMSpc Downloads. Rename the current Silverleaf icon on your desktop to “3.x” Open the link, save it to C:\ or desktop and install, though you need to also rename the ‘default installation directory’ (VMSpc) to something like VMSpc 2.5. Rename that new desktop icon to “2.5” also. This is just to allow having both programs available. You’ll need to copy your trips and gauge over–my_really_great_gauges_screens.scn for example.


What do the LEDs on the JIB tell me?

The green LED should be on solid when the JIB is powered. The red LED should flash indicating that it is alive and running. Specific red LED blinking behavior depends on the model of JIB.


Slow blink: JIB is not receiving engine data.

Fast blink (flicker): JIB is receiving engine data


The JS501 may be connected to one or two different engine data busses. They are referred to as J1708 and J1939.

Single blink: JIB is not receiving engine data.

Double blink: JIB is receiving J1708 data.

Triple blink: JIB is receiving J1939 data.

Flicker: JIB is receiving data from both data busses.


Which JIB model do I have?

JS540 Bluetooth / JS550 WiFi JIB These two look identical from the outside. They’re functionally the same as the JS501 though you see there’s just the single 12-pin connector.

JS501 The JS501 is the current USB version in the VMSpc kit. It has a USB port and two engine communications modes available (J1708 & J1939) in a single 12-pin connector.

JS500 The JS500, sometimes also referred to as the “Classic” JIB, is the predecessor to the JS501 JIB. It has a 9 pin serial connector and supports the J1708 engine data bus.

Original JIB The first JIB sold. It is functionally the same as the JS500. It just has different connectors on it. For the purpose of this FAQ follow the JS500 directions.


Which software version should I use?

If your coach was made in 2006 or earlier, you should use version 3.x. If your coach was made in 2007 or later, you should use version 4.x.


Why can’t I buy this online?

There are many variations in coaches across many years, brands, and models. Each has its own concerns and so it’s very easy to order the wrong equipment. Try the software for free; then call us without any obligation at all.


Will VMSpc work on my Mac?

VMSpc only runs on Windows. However Macs can run Windows. There are different methods of doing this. One is by using a virtual Windows session through the Mac OS. There are a number of programs that can do this. The most popular are Parallels Desktop and VMWare Fusion. There is also an open source program called Virtual Box which is free of charge. Another method is by partitioning the hard drive and running windows directly from the Mac separate from its own OS. This only works if the Mac has an Intel processor. This is accomplished through using Boot Camp which is included in Mac OS 10.5 and later. Follow this link for more information on using Boot Camp:


Will VMSpc work on my tablet?

VMSpc, as a Windows program, works on tablets and lap-tops using the Microsoft Windows operating system. Windows XP, Vista, 7,  8 , 10 and 11 are all compatible. Devices that have been upgraded from Windows 10 to Windows 11 may have some driver issues. Windows RT will not work. Windows 10 works great on most tablets yet the ‘S’ version will need converting to non-S. A web search will reveal the procedure for this conversion. 


Will upgrading to a newer version overwrite my old v2.5x or v3.x screens?

No. V4.x is isolated from old installation(s) you may have.


Windows Defender keeps deleting the installer. What should I do?

Windows Defender keeps deleting the installer for VMSpc 4.x, declaring it malware. This is a problem with Windows’ part and requires this workaround: Disable Defender, download, install *then* re-install it.