Wireless Door Lock Sensor

["Tom" <gigela@xxxxxxxxxxx>]

I would like to install door lock sensors on an existing Ademco alarm.
Ideally I would like to use wireless sensors such I do not have to run
additional wires.

Is there any readily available door lock sensor that can be added to an
existing installation? (preferable wireless)?

I searched but actually hardly found any info on such sensors. I would
have though that should have been actually a standard part of any alarm
to confirm that all doors are locked (and not only closed) before
arming.
Any insight why this is not considered standard or important? What is
the point of arming the alarm and leaving the back door unlocked?

Of course I had a alarm salesman in the house right after I bought it
and asked him about door lock sensors and I got a more then
disappointing answer (same for asking for some form of protection if
the phone line is cut). It seems you can get much out of the sales
people such I decided I would rather build the alarm myself.

Tom