The X-10 security RF protocol differs from the one they use for lights and appliances but both are based on the NEC IR protocol. You can see details here...

     [Link: mbx-usa.com]

The security codes cannot be sent with standard X-10 RF transmitters but only with their security remotes.

If within RF range (poor with most X-10 RF), I can disarm any X-10 RF security console in under 30 seconds. In this case, I think security is a misnomer.