transponders

I'm guessing a transponder is a device where you actually put your original spare key (with chip in key) into this black box and when you press your alarm the key will turn on???????    so whats the point of having a immobilzer when the key is in your car?  the thieves can take out that key and drive your car away?????      well..  i believe my insurance company wouldn't like the idea that i had my spare key in the car =P   I'm confused =(

i'm new to transponders, so I'm wondering the same thing myself.

well a transponder is only needed for cars that have a remote start being installed in a vehicle that has a transponder anti theft sytem. There is a  lot of keyless modules available for certain cars that require no key ,they just learn the code and send it back upon remote start,this way there is no need to worry about someone finding your key .. Sometimes you will have a car that a keyless module will not work and the use of a spare key is mandatory in this situation the head of the key can be cut off making the key useless to start if found.If you dont want to cut the head of the key off, you can open it up and take the liitle transponder out of the key and use that .Finnaly if the customer does not want to use his spare key and needs a new one then what i do is have my locksmith who does transponders code me a key but not cut it so this way it will not start the car only send the code.