Autopage XT-1100 Here is a question, how do I program the XT-1100 key fob to alert me when the alarm is triggered on my vehicle??

This works for alarm only. If you have remote start as well, you will need to press the valet button 3 times. The valet button is a small red button that was probably placed somewhere along your lower dashboard under your steering column. It is to put the alarm into "valet" mode when you use it, which is basically to temporarily override the unit. The valet button is used as part of the programing process in addition to being how the valet feature is turned on and off. How to program AutoPage XT remote

Aftermarket alarms have to be configured to bypass the factory alarm system when using it.
I don't mean you have to permanently delete your factory alarm. What I am saying is, when you use your autopage key fob to unlock your doors, it must also send a signal to the disarm wire of your factory system simultaneously. If not, your alarm will go off just like you are experiencing.

could be your car requires a bypass module... or the safety inputs preventing the alarm from starting car are in place... without knowing your make/model that's the best I can do...

If you need further help, reach me via phone at https://www.6ya.com/expert/jonathan_4cd718ed254374ee

Here you go. These are easy to program.

If you put remote in your pocket or your purse make sure it doesn't push on any buttons!

how do I reprogram the xt-43lcd

I see this is a old post but, I have this unit in a used van that came with no remotes. A local audio shop paired it up with a AUTOPAGE XT-33. I can lock,unlock,start with this remote. Just remember to keep the drivers open while doing these steps.
1. Turn the Ignition 'switch 'OFF/ON' 3 TIMES and stay in
ON position. Within 15 seconds.
2. Push the Valet switch 2 times and hold in on the2ndpush, when a long chirp is heard then release the valet
switch. You are now in the Transmitter programming mode.
Program:1. Press the Lock button on transmitter 1 until the siren
responds on Car with a confirming chirp; the first
transmitter is now programmed to Car.
Exit: Turn Ignition to 'OFF' position, or leave it for 15
seconds. 3 long chirps will confirm exit.
Note: If more than 4 transmitters programmed, the system
will only keep the last four.
The Valet switch is a little Red Push Button that should be
mounted under the lower left side of you dash or in the lower
left kick panel near the E-brake pedal.

If this is the vehicle's factory alarm that is being triggered then your factory alarm must be disarmed prior to the remote starter sequence. The Autopage unit has a factory disarm wire available for this purpose. When the alarm triggers again try turning the key in the driver's door to see if there is a factory disarm wire available in the vehicle or if the factory alarm is RF disarm only. If it is the after market alarm that is being triggered then you made need to decrease the sensitivity.

http://www.autopageusa.com/resources/C3RS665installmanualfinal.pdf

you will find this in the programming features in the link above.

you will need to press the battery hold down back in.