cable for megajolt

john057 · Post by **john057** » Fri May 13, 2011 6:17 pm

hi, i am trying to connect my megajolt ecu to my laptop, the ecu has uses a rj11 phone cable and my laptop has a 15 pin serial port and a usb port.
is it possible to wire the rj11 cable to a usb cable? both cables have 4 wires. if not can anyone tell me a cheap way to connect the ecu to the laptop
THANKS

spandit · Post by **spandit** » Fri May 13, 2011 7:11 pm

No, the MegaJolt communicates on a different protocol and you need some hardware in between the MJLJ and the USB port for it to work (you need a Serial-USB converter). Don't try plugging it into the phone port on your laptop - won't achieve anything and could damage things

capri_turbo · Post by **capri_turbo** » Fri May 13, 2011 7:38 pm

the 15 pin port you describe will be a VGA output not serial. It's for connecting an external monitor.

john057 · Post by **john057** » Fri May 13, 2011 8:16 pm

ok, so what exactly should i be looking for? thanks

spandit · Post by **spandit** » Fri May 13, 2011 8:50 pm

Your MJLJ should have come with a cable that plugs into the RJ11 on the MJLJ and terminates in a 9-pin serial plug (female pins). You need a cable with USB at one end and a serial port (male pins) at the other. I bought an FTDI chipset one

john057 · Post by **john057** » Fri May 13, 2011 10:32 pm

ok, would these two do the job
http://cgi.ebay.ie/NEW-DB9-Female-RJ-11 ... 4158e22d8a

http://cgi.ebay.ie/USB-SERIAL-RS232-DB9 ... 230f7fafa2

spandit · Post by **spandit** » Sat May 14, 2011 7:08 am

Yes, I think those would do the job

john057 · Post by **john057** » Sat May 14, 2011 8:08 am

ok thanks for the help

john057 · Post by **john057** » Wed May 18, 2011 3:33 pm

ok i got the cable and adapter in the post today but i am not sure where to put in each pin in this adapter, can anyone help?

here is what it looks like

spandit · Post by **spandit** » Wed May 18, 2011 3:50 pm

This should help:

http://www.autosportlabs.net/asl_dist/m ... n_v4.x.pdf

john057 · Post by **john057** » Wed May 18, 2011 5:32 pm

i had a look at that and i still cant really figure it out, if i new the colours of which wires to use it would help. also do i need to solder wires 3 and 4 together?

spandit · Post by **spandit** » Wed May 18, 2011 7:27 pm

The pinout is of the back of the connector so looking from the outside, pin 5 is top right. If you are behind the connector and can see the wires, it's on the left

john057 · Post by **john057** » Thu May 19, 2011 5:19 pm

ok i think i have the cable sorted now, but when i connect it to the laptop and ecu how can i tell if it is working,
when i plug it in no message comes up ont the laptop saying that it is connected

spandit · Post by **spandit** » Thu May 19, 2011 5:32 pm

Have you read the installation and operation guides?

Once they're connected you should be able to read the default map off the MJLJ by clicking the first arrow button on the toolbar

john057 · Post by **john057** » Fri May 20, 2011 1:39 pm

ya i read the guides, when i turn on the ignition the light comes on the ecu so i know that works, so it must be a bad connection between the ecu and laptop