cable for megajolt

General Topics for configuring, operating and tuning the Megajolt. Also see the <a href="http://www.autosportlabs.net/MJLJ_V4_Operation_Guide">Operation Guide</a>

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john057
Posts: 25
Joined: Sat May 07, 2011 10:17 pm
Location: ireland

cable for megajolt

Post by john057 »

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
Posts: 129
Joined: Wed Dec 22, 2010 10:43 pm
Location: East Sussex, UK

Post by spandit »

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
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Joined: Tue Jan 10, 2006 8:17 pm
Location: North Yorkshire, UK

Post by capri_turbo »

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

john057
Posts: 25
Joined: Sat May 07, 2011 10:17 pm
Location: ireland

Post by john057 »

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

spandit
Posts: 129
Joined: Wed Dec 22, 2010 10:43 pm
Location: East Sussex, UK

Post by spandit »

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
Posts: 25
Joined: Sat May 07, 2011 10:17 pm
Location: ireland

Post by john057 »


spandit
Posts: 129
Joined: Wed Dec 22, 2010 10:43 pm
Location: East Sussex, UK

Post by spandit »

Yes, I think those would do the job

john057
Posts: 25
Joined: Sat May 07, 2011 10:17 pm
Location: ireland

Post by john057 »

ok thanks for the help

john057
Posts: 25
Joined: Sat May 07, 2011 10:17 pm
Location: ireland

Post by john057 »

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

Image

spandit
Posts: 129
Joined: Wed Dec 22, 2010 10:43 pm
Location: East Sussex, UK

Post by spandit »


john057
Posts: 25
Joined: Sat May 07, 2011 10:17 pm
Location: ireland

Post by john057 »

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
Posts: 129
Joined: Wed Dec 22, 2010 10:43 pm
Location: East Sussex, UK

Post by spandit »

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
Posts: 25
Joined: Sat May 07, 2011 10:17 pm
Location: ireland

Post by john057 »

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
Posts: 129
Joined: Wed Dec 22, 2010 10:43 pm
Location: East Sussex, UK

Post by spandit »

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
Posts: 25
Joined: Sat May 07, 2011 10:17 pm
Location: ireland

Post by john057 »

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

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