Douglas Butler <PICLIST@mitvma.mit.edu> wrote:

> I thought I knew basically how the rolling code keyless entry systems
> work: the transmitter and receiver generate matched pseudorandom
> sequences, the receiver has to look several codes foreward of the
> current code in case someone hit the button while out of range, etc.
>
> My question is how do they handle multiple transmitters?  My wife's car
> has two transmitters and one sits on the shelf for months on end, but
> both work.  Does the receiver have to know there are multiple
> transmitters out there and keep track of pseudorandom sequences for
> each?

Doug:

No, the receivers don't HAVE to work that way, but most of them do.

-Andy

=== Andrew Warren -- aiw@cypress.com
=== Principal Design Engineer
=== Cypress Semiconductor Corporation
===
=== Opinions expressed above do not
=== necessarily represent those of
=== Cypress Semiconductor Corporation

--
http://www.piclist.com hint: To leave the PICList
mailto:piclist-unsubscribe-request@mitvma.mit.edu