I'm struggling to find anything more than "executive summaries" describing the HomeLink products common in most modern vehicles.
I'd like to know their capabilities as well as some general implementation details regarding how much latitude they have in their application.
I.e., do they always use the same carrier frequency? Same coding scheme? (presumably can differentiate between rolling and fixed codes just by "listening"? Or, do they "know" the common formats in use?)
So far, my search terms haven't led me to anything beyond
The Homelink web pile deal primarily with standards and points users to the various vendors. It's basically a fancy garage door opener.
Last resort is to dig throught the relevent patents. For example: "Universal garage door operating system and method" See the patent citations list at the bottom for more pointers.
Surely you jest. The first thing members of a consortium do after approving a standard is to impliment proprietary enhancements. Product differentiation by frequency is epidemic. The list is for UK devices. US uses a different set of frequencies. For example the 868MHz frequencies listed are 915MHz in the USA. These
800/900 MHz frequencies are recent additions as older Homelink devices would only go up to about 400 MHz.
It can do both rolling and fixed codes. See that above PDF. I've never bothered to look at how it handles this during pairing. My guess(tm) is that it has a table of known devices and scans them all in sequence until it finds a match.
I'm not up to date on the latest politics, but as of a few months ago, there were compatibility issues between pre 2011 devices and current devices. The fix was a "compatibility bridge" device. See the 12th question under the FAQ at:
--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.