Keyless FOB technology?

[R_W_B]

While in <....> . Does the FOB constantly transmit a signal, or does the ECM constantly transmit a signal that activates the FOB when it is in range? What kind of signals are involved (IR, radio, microwave), and what is actually "switched on" in the ECM to allow starting? Will the FOB battery go dead quicker if it is always kept close to the bike?

Seems like I read which one transmits one time but can't remember for sure. I would think the ECM does the transmission since it is hooked up to a more resourceful battery. But then I really have no idea how much power it takes to transmit or receive. In fact they both might transmit with a sort of handshake scenario like a computer modem does.
I think it's probably radio (below 1,000,000 frequency) waves. I think the phone company uses microwave technology for it's transmission towers. Would imagine micro wave frequency would be overkill and more expensive. But I don't really know. The ECM is probably a micro computer unit but that has to do with cycles per second (megahertz) not transmission waves.
I would not think storing the FOB near would cause the battery life decline since this would be the same as riding. But again I don't know for sure.

But I do know a bit about computer technology and I would think there is a cmos gate inside the rom chip of the ECM that is normally open, and when it finds (handshakes with) the code value of the FOB it closes and completes the circuit. OR if you input the user code (you set previously) thru the use of the turn signals, it would close and complete the circuit. I carry my preset user code with me written on a card in case my FOB battery goes dead etc. That way I can get home. The FOB and the ECM are matched at the factory with a certain code value. If you buy a new FOB the dealer has to program a new match up. Each FOB is only good for one ECM. Depending on how many bits HD implemented into the storage rom would be the amount of FOBs that could be produced. If it was 32bits wide then there could be 4gig (about 4 billion) FOBs on the road and still not have a duplicate.

 

[Breeze3at]

RWB; Thanks for the info. I just looked "keyless ignition" up on 'How Stuff Works'.
They have a good explanation of the system(s). They can be hacked by a laptop with the proper hardware, software and time. So if you see someone with a laptop hanging around a parked Harley or yourself with a fob in your pocket, he may be up to no good. Nerds with pocket protectors probably are ok though. They did say tinfoil wrapped around the fob blocks or drastically
cuts down on the send/receive signal.

 

[R_W_B]

RWB; Thanks for the info. I just looked "keyless ignition" up on 'How Stuff Works'.
They have a good explanation of the system(s). They can be hacked by a laptop with the proper hardware, software and time. So if you see someone with a laptop hanging around a parked Harley or yourself with a fob in your pocket, he may be up to no good. Nerds with pocket protectors probably are ok though. They did say tinfoil wrapped around the fob blocks or drastically
cuts down on the send/receive signal.

Yes these are usually brute force software programs. What they do in the basic context is run many possibilities of the matching code thru. A computer is very fast. Most instructions on a modern processor takes about 19 or so cycles. But most of them run now at 1.2 million cycles a second (some faster). So divide 1.2 million by 19 and that is how many instructions are happening in one second. So given enough time it can literally try all combinations of the code. It does have to have knowledge of any encryption used though but not sure HD uses encryption. Luckily our banking system does. This is why I don't let any computer "remember me" on my banking passwords. Because the algorithim used to store windows passwords "is" known. All they need is enough time to download all the stored password data and then they can work on it at their location. It's a bit more involved than that but in any case any important passwords I don't let the computer remember them.