analog vs data

phil6710 wrote: Analog is a direct signal like w2w connections they are either 12v+ or a ground pulse. Data would be coded information sent via multiplex signal.

So by "analog" you mean "digital"?Kevin Pierson

I guess by analog I mean "hard wiring" with out the use of a bypass module. We call it analog at the shops I install for. I contract with several differnt shops for installs. The question I am getting at is it justifiable to charge less for an install that will cost less in parts but will take more time to install vrs. using a bypass mod which cost more but usualy saves time in labor. Basicaly someshops I work for will charge less if the customer sacrifices a (transponder)key and a "data" bypass is not used. But there is more connections to make with this type of install and it takes more time.

KP - how do you define digital? Hence what is digital and what is analog as you see it in this case?

To the first poster, why oh why didn't you just ask for the difference between hard wiring and D2D?

oldspark wrote: KP - how do you define digital? Hence what is digital and what is analog as you see it in this case?

Digital signals have two levels - high and low. Basically any signal that looks for either ground or 12vdc to determine the status of the input (in a car environment). Analog signals have specific values for points along the way from the high and low. Analog signals would be 0-5vdc, 0-10vdc, 4-20mA, etc. What would a definition of "analog" be that would actually fit in this context?Kevin Pierson

Ah - but hi & lo can be 0 & 1 or 1 & 0. EG RS232 "1" is a -ve voltage whilst "0" is a +ve voltage.... Alas I tease with the irrelevant. The point is that you have described analog quantities. As the saying goes, "there is no such thing as digital transmission" - it is all analog. (So too are logic levels, but there is FWIR a possible "digital" state.) Hence my comment that it doesn't matter what you are installing, wire-wise it is all analog.

oldspark wrote: Ah - but hi & lo can be 0 & 1 or 1 & 0. EG RS232 "1" is a -ve voltage whilst "0" is a +ve voltage.... Alas I tease with the irrelevant. The point is that you have described analog quantities. As the saying goes, "there is no such thing as digital transmission" - it is all analog. (So too are logic levels, but there is FWIR a possible "digital" state.) Hence my comment that it doesn't matter what you are installing, wire-wise it is all analog.

But I did not describe analog quantities I described properties of digital signals. To be digital there has to be a high/low threshold. Therefore, having potential is a requirement of a digital signal. A door pin, for instance, is either ON or OFF, High or Low, 1 or 0, +12vdc or ground. A purely digital signal! The same thing for a tach signal, it is either + or -. Kevin Pierson

Enough already, you two, you're both right in your explanations. I bet the original poster is ruing the day he used the D word. How about adding that digital signals also alter the time base?

LOL! I prefer to avoid "digital" in such situations - people expect computational circuits. I don't think of my headlights as digital despite their on-off state. (I was gonna say hi-lo state...) I might define & use "digital" to distinguish between (say) my on-off & dimmer outputs for lights etc (digital & analog signals respectively), though discrete and variable are probably the correct terms. But when I see PWM described as digital.... and that's even less digital than Morse Code (which is officially NOT digital). Digital signals are analog - albeit discrete levels. It's like "digital transmission" - there is no such thing - all transmission is analog, but there is "digitally encoded" transmission. (And that is usually tri-state - eg, RS232, fibre-optics etc, hence also not "digital".) And of course NEVER confuse high or low outputs with low or hi voltages or on-off or active or inactive states. Alas a very common digital signaling term is "active-low" which is usually regarded as a (digital) "high".    To use "logical" jargon is more acceptable - eg, I can say I'll switch my light off, or de-active-ate it or send it low. But if I were to say my wall switch is digital - or I had a digitally controlled light - I think people here would object. And if anyone goes psycho over this, we can blame Boole for his invention of Boolean algebra way before even electronics existed (and computers were still analog).    As always - especially in English - we need to define our jargon when it matters. (And people wonder why "Legal English" exists!) Over & Out. aka going low.... I mean, not-active = nactive.

Surely if you use your finger to turn it on or off a light switch must be digital. Sorry Peter you asked for it.