From Newsgroup: sci.electronics.misc

A question concerning the car remotes; door lock, headlights, etc.

Each car/handset must be a matched pair, regarding the ID
and security codes. Obviously only one car in the parking
lot ought to respond.

Are the ID codes determined by each manufacturer, as
they choose? Or is there an intern'l body which allocates
them, such that each is guaranteed unique, just as
every telephone has a unique number?

Additionally, anybody know anything about their modulation
methods, or FCC regs? i.e. simple on/off key?

--
Rich
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From Newsgroup: sci.electronics.misc

Rich D wrote:

A question concerning the car remotes; door lock, headlights, etc.

Each car/handset must be a matched pair, regarding the ID
and security codes. Obviously only one car in the parking
lot ought to respond.

Are the ID codes determined by each manufacturer, as
they choose? Or is there an intern'l body which allocates
them, such that each is guaranteed unique, just as
every telephone has a unique number?

Well, they have a chip that is programmed at the factory, probably with a sequentially-incremented number. The car is then trained to accept several key's serial numbers. The all-in-one keys/fobs have two chips, one operated by pushbutton with a coin cell for door unlock, and one RF-powered by the engine computer through a coil near the ignition lock, for immobilizer.
So, in theory, there should be no two cars anywhere that respond to the same code.

Jon
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From Newsgroup: sci.electronics.misc

OnFebruary 18, Jon Elson wrote:

A question concerning the car remotes; door lock, headlights, etc.
Each car/handset must be a matched pair, regarding the ID
and security codes. Obviously only one car in the parking
lot ought to respond.
Are the ID codes determined by each manufacturer, as
they choose? Or is there an intern'l body which allocates
them, such that each is guaranteed unique, just as
every telephone has a unique number?

Well, they have a chip that is programmed at the factory, probably with a sequentially-incremented number. The car is then trained to accept several key's serial numbers. The all-in-one keys/fobs have two chips, one operated by pushbutton with a coin cell for door unlock, and one RF-powered by the engine computer through a coil near the ignition lock, for immobilizer.

So, each manuf'r has its own allocation of ID numbers. And, presumably, its own
RF format. Are there FCC regs on that?

So, in theory, there should be no two cars anywhere that respond to the same code.

Well, no. There's no intern'l body allocating the codes, so in theory, there
could be duplication.

Whereas, in the phone network, you dial a number, it's guaranteed to ring exactly
one target device.

--
Rich
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From Newsgroup: sci.electronics.misc

In article <6a0dcc88-715f-4d67-8a14-45819e1744a5n@googlegroups.com>, rdelaney2001@gmail.com says...

So, each manuf'r has its own allocation of ID numbers. And, presumably, its own
RF format. Are there FCC regs on that?

For many of the low powered devices the FCC just states what frequency
and power level they can use. Just about anything else is up to the
designer. Very little FCC regulation.

They are unlicensed devices and often stated that they must accept any interference and not cause any to a licensed service.

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