Transmitting an all is well packet from sensor to main control unit

[mister accavanno <mraccavanno357@xxxxxxxxx>]

Ok, let's say the sensor is communicating with the MCU via a 315mhz,
433mhz, or 868mhz frequency. I understand that the system can be
jammed and thusly the MCU will not be able to receive the (all is ok,
I am here, everything is fine packet) from the sensor and when that
periodic packet is sent and not received by the main control unit, the
main unit will send out an alarm or a trouble message to the
monitoring station. I would like to know if that is the only
transmission that is sent by a sensor that is functioning in an armed
mode( armed, meaning alarm has been set and home owner or business
owner has gone home for the night). I am assuming that the sensor is
idle except for the moments when transmitting these packets, or when a
person passes the area which the sensor is protecting, thus
transmitting a message to the MCU that the closed loop has been broken
by detecting the moving heat of a person walking by it. So the
question I am asking is: What does the sensor transmit to the MCU, and
how often? Does it just send a burst of 315, 433, or 868mhz rf, or
does it actually send an encrypted packet of some sort. What does that
packet contain(a certain amount of bits, or rf pulses, or what?). And
how often are these sent ( as in minutes, hours). I have certain
discussions which I would like to initiate depending upon the
responses I get from this post. I think the professionals with the
knowledge to answer the above questions would be interested with what
I have to say about this. Now, I am new in the alarm installing
business, but I have noticed some things recently.