data systems
Printed From: the12volt.com
Forum Name: Miscellaneous - Off Topic
Forum Discription: Topics that just don't fit anywhere else.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=108389
Printed Date: May 13, 2025 at 6:01 AM
Topic: data systems
Posted By: t&t tech
Subject: data systems
Date Posted: October 24, 2008 at 7:34 PM
how do these data systems work exactly on these new high end vehicles, love installing but my market is the easiest in the world i believe, cars like bmw, volvo. audi, volkswagon, we never encounter
-------------
COMMIT YOUR WAY TO JEHOVAH AND HE WILL ACT IN YOUR BEHALF.
PSALMS 37:5
Replies:
Posted By: howie ll
Date Posted: November 16, 2008 at 4:08 PM
T&T, disclaimer, this is to MY knowledge and I might be wrong. Data simply means sending more than one voltage down a wire to operate something, e.g. 12v+ to switch, detente 1 to side lights, detente 2 to headlights etc. A CAN or multiplex system is one where that wire may be used for more than one function, e.g. measure a voltage or resistance across that wire from the switch to the ground on the other side of the bulbs and you have a failure warning light, have you come across Chrysler one wire locking where you grounded to lock and went through about 600r to unlock? That's a multiplex system where the same wire gives 0volts (from 12v+) to lock and about 5v+ (from 12v+) to unlock. With CAN you have processors eg Body control modules sending out the power i.e.12volts or e.g. lock motor wires and the switches sending very low current low voltage signals to the processors. This saves on weight, cable thickness etc etc. Examples would be current GM, On Star, and indicator clicks, ignition, VSS and illumination through a pair of wires, current BMWs with back-up warning through the radio and Peugeot/Citroen sending data to high level display driven by the radio, in fact if fitting a new head unit to one of these we ignore the radio acc line and find a new one from either the ignition or fusebox. I realise Chris would probably do better but I hope this gives you some grounding if you will excuse the deliberate awful pun.
Posted By: t&t tech
Date Posted: February 16, 2009 at 9:27 PM
care to add anybody, thanks howie
-------------
COMMIT YOUR WAY TO JEHOVAH AND HE WILL ACT IN YOUR BEHALF.
PSALMS 37:5
Posted By: howie ll
Date Posted: February 17, 2009 at 3:54 PM
Yes we finally got you and on your home ground. I've just realised adding a Y to final also adds an "L". Is this what they mean by going two 'ell? Sorry, been one of those whymsical days
Posted By: robertsc
Date Posted: February 17, 2009 at 8:48 PM
Posted By: KPierson
Date Posted: February 17, 2009 at 9:09 PM
A data system is simply a way to transmit more then one signal on a wire - there are a ton of different ways to acomplish it. There is voltage monitoring - It is possible to use one input pin on a microcontroller and have 1024 different possibilities (on a 10 bit system). On a 5 volt system this gives a resolution of ~0.005 vdc. As you can see, you can send all kinds of info in to the microcontroller based on this resolution. The "down side" here is if you try to send more then one signal (like from two switches) at a time you either confuse the processor, or you have to break down the voltage in to known parts and determine what all signals are present. Then there are switching matricies - commonly found in Nissan/Infiniti vehicles in order for the BCM to communciate to the accessories on the steering wheel (lights, turn signals, fog lights, etc). The Nissan system uses 5 outputs and 5 inputs (10 total wires) and ends up with 25 total possibilities. They use 5 possibilities for diagnostics leaving them with the ability to send 20 signals down 10 wires with no possibility of "confusing" what switch is on at any given point. This is the same theory behind how computer keyboards work, and is a very popular way to control a large amount of IO points with a minimal amount of IO. Then there are serial communication lines. These can be done in a variety of different ways, and CAN and LIN networks would be examples. You basically send data in a series of predetermined ons and offs (or 1s and 0s) between two intelligent devices. The data encoded in the message is unlimited and can be virtually anything in the car. Most manufacturers stick to standards that dicate things like how a message is started, how conflicts are resolved (if two modules try to "talk" at the same time), the format for the message, and other perameters that are required to make an error free, reliable system. CAN networks are cool because you can theoretically cut one of the two wires and the bus will continue to send info - just at a much slower rate. If you have some free time read up on CAN networks, they are fairly ingenious in their implementation. ------------- Kevin Pierson
Posted By: howie ll
Date Posted: February 18, 2009 at 2:02 AM
I just want to thank robertsc and KP for their inputs. What you both wrote is extremely interesting but completely over my head so I'm going to use the link above. You can never have enough knowledge.
Posted By: t&t tech
Date Posted: February 18, 2009 at 5:52 PM
great info guys, it's apprcieated, howie, wat's up,see even you liked the info, anyone else care to add, it would be welcome.
-------------
COMMIT YOUR WAY TO JEHOVAH AND HE WILL ACT IN YOUR BEHALF.
PSALMS 37:5
Posted By: howie ll
Date Posted: February 18, 2009 at 8:07 PM
I need the info so I can stop refusing to touch 04 onwards Audis, BM's and Mercs!!! I still bet no one can get an R/S on to a magic key Mercedes yet. I'm unhappy...(there moderators you don't have to change one word) because I spent the afternon doing a cheap and nasty unkown brand R/S in a manual VW, the "tach" sense is a wire wrapped 5 turns around the HT wire  , one of the remotes (2 way) failed to work out of the box, there's no status output so I had to pull the antenna ring from the ign. switch and stuff a key in it rather than a by-pass box, and I've just got back from installing a tracker in a truck. Midnight job but he never turned up till 00:45 and I've just got home! You wonder why I get cynical? Did you see how I got the why in there?
Posted By: t&t tech
Date Posted: February 19, 2009 at 3:53 PM
howie when are you gonna let me install an alarm with ya,  , i see now why you're cynical sometimes, don't worry they'll invent something for the magic key soon, or maybe you can, lol, i really have to see a mercedes with this magic key, i've never seen it, but then again how often do you see a merc. on the road in my parts, lol ------------- COMMIT YOUR WAY TO JEHOVAH AND HE WILL ACT IN YOUR BEHALF.
PSALMS 37:5
Posted By: howie ll
Date Posted: February 19, 2009 at 4:45 PM
It's a plastic piece, goes into a rectangular slot and you push to start or push it home and press a starter button. Most UK Fords have it now, Renault use a credit card sized magic key which goes into a slot, this releases the steering wheel lock solenoid, etc etc. The Chinese piece of junk turned out to lock the car, then the alarm triggered off, I disconnected the shock and prox, checked door trunk and hood contacts, all OK, no juice coming from ign 1. Thought sod it, I've spent a day on this so I managed to sell him a Concept 650 ll and Intellistart to rescue the situation. Wrong about the cricket wasn't I, don't know if you watched it on TV but did you see the woman in the lime green dress? Thought she was going to have a heart attack!
Posted By: robertsc
Date Posted: February 19, 2009 at 8:46 PM
howie ll wrote:
I need the info so I can stop refusing to touch 04 onwards Audis,
i see on bypasskits site they have a bypass for Volkswagen Touareg and a8 its called a kivw
Posted By: t&t tech
Date Posted: February 20, 2009 at 5:10 AM
i must admit howie, i was wrong about the cricket to, but then agiain i had good reason, given the records ot the west indies in recent times, but they did well i must say, congratulations to them, and possibly a new era of windies cricket, that could remind true fans of the real west indian spirit for the game, hmmmmm, left to be seen.
-------------
COMMIT YOUR WAY TO JEHOVAH AND HE WILL ACT IN YOUR BEHALF.
PSALMS 37:5
Posted By: howie ll
Date Posted: February 20, 2009 at 12:02 PM
Hold on robertsc, ta for that info but I stil haven't used the link you already sent me. I will point out that we fitted a DVD player in an 05 Touarag (we call them toerags...don't ask), the guy got an A7 last year and the CAN adaptor Nav TV? wasn't compatible with 08 VAG group cars, the problem as I see it is as soon as they bring a kit out, the manufacturer changes the software and moves the goal posts. VAG being the worst, hands up on this forum who hasn't managed to trigger an airbag or engine fault warning light on a VW/Audi? Darren we were both wrong about the cricket. Incidentally one gets the impression you get a mixture of older Brits, older yanks and various Nissan Toyota and Honda but none less than 5 years old, I'm not being rude but how wrong am I?
Posted By: robertsc
Date Posted: February 20, 2009 at 1:40 PM
well thats not bad guessing what crystal ball did you use? actually in my town i am considered the starter guy the only other ones doing are the big boxes i have about 15-20 years of starters under my belt i average about 200 starters a winter and i get everything but mostly gm ford chrysler saturn honda and toyota i did one audi a4 this year one volvo s60 and a bmw the magority of vehicles are probably less than 5 years old i would say that ford was the most popular this year last year it was toyotas i live in a small town 50,000 with drawing of close to 250,000
Posted By: t&t tech
Date Posted: February 20, 2009 at 3:34 PM
you're quite right howie, i deal in mostly asian vehicles, but i like to learn just so i know, surely you understand, like you said, "you can never have enough knowledge", and very rarely do delve into vehicles up of 5 years.
-------------
COMMIT YOUR WAY TO JEHOVAH AND HE WILL ACT IN YOUR BEHALF.
PSALMS 37:5
Posted By: howie ll
Date Posted: February 20, 2009 at 3:41 PM
Actually Robert? I was thinking of t&t, he's in the West Indies and because of some of his previous post and I know that like you he is part of the Empire....Please get used to my surreal sense of humour, the master is Kar Tune Man, number 2 is I am an Idiot. Over here I'm probably doing more R/S than any one, = 40+ per year, BUT it's a dieing market. That Chinese rubbish "SPY ALARMS" turned out just like thought so I wasted a day installing it ripping it out and starting over. Remember here it's Cat l alarm, I'll define that in a sep. post if you're interested, plus R/S. Never done a stand alone R/S. Talking of big sounds, I neither can be bothered, I'm 62 and I can't be asked to pull back seats, lift sub boxes etc!
Posted By: howie ll
Date Posted: February 20, 2009 at 3:44 PM
P:S to robertsc, in Europe, DEI is the R/S product, we are stuck with what they bring over, I've spoken to Fortin and they won't export because they feel the software is too different on Euro Cars. Anyway for 40 vehicles a year who am I to ask?
|