Author Topic: VEMS communication methods.  (Read 9973 times)

Offline gunni

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VEMS communication methods.
« on: February 09, 2009, 05:41:38 pm »
There are a few way to connect to your VEMS unit.

#1. Your laptop has a serial port (9pin connector on the back, two rows high)
#2. You have a USB - Serial converter
#3. You have a pcmcia serial port

All of the ways use a RS232 protocol to communicate with the unit. The only difference is the interface with your laptop/pc.
All of the ways suggest you use the same type of cable for connection.

Here is an explanation to each of the ways.

Here you simply connect your serial cable to the unit and select the appropriate COM port in the tuning software.
Since this is a built in serial port it´s almost surtenly COM1 or COM2.

Here you have an adapter that uses the USB on your laptop, When you connect the adapter to your laptop for the first time you may need to install drivers that came with it. After the drivers are installed your adapter is ready.
If you are not sure what COM port it´s registered to you can Try this.

Right Click "My Computer"
Select "Manage"
Find and select "Device Manager"
Find and select "Ports (COM and LPT)"
There you should see what COM ports you have installed, If there is nothing there then your driver installation failed or the adapter has failed. Most likely you have the one port that is there. Use that in your tuning software. When you remove the USB adapter and later put into another USB port, the COM number will very likely change. So it´s a good idea to use the same port everytime,

Here you use the almost never ever used PCMCIA slot on your laptop to connect a serial port to.
The card will come with a driver which you must install. The benefit of pcmcia over USB would be that the card it self is less likely to come loose from the laptop like a USB cable can do. It is basically the same as installing a USB adapter, you need to use the driver disc that came with the card.

A trick to TEST if your laptop is communicating through the serial port would be.
To bridge pin 2 and 3 of the serial port. Go into the terminal program that came with your megatune package.
Select the right COM port and connect.
When you write anything in the Transmit dialog box and hit send
it should immediately show up on the Receive box.
This will make sure that your port is working.

I´m posting this cause I received my pcmcia card today, It was less then 10pounds shipped from Hong Kong(within 10days shipping time). I was going to get a dedicated tuning laptop, now I don´t have to and don´t have to use a flimsy usb adapter.
Here is a link to ebay with these cards.

Just tried it out with the cheap ebay card. Works just like a built-in serial port.
« Last Edit: February 10, 2009, 11:57:29 pm by gunni »

Offline PeepPaadam

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Re: VEMS communication methods.
« Reply #1 on: February 11, 2009, 02:30:48 pm »
It should work much better and faster, because it is basically hardware RS232 converter not emulator like USB->RS232.