I did not have an exact answer for your SH624's Security Light Button function. So I set up an X10 signal monitor and tried it. It sends the Lower address when activated.
The KR32A and KR10A send the higher address. When their Lights On and Off buttons are used.
Results attached.
So the Security Light buttons on the SH624 control the House Code and Light Code set in the Options Menu of the SC1200A.
The KR10A and KR32A keyfobs light buttons do the second higher Light Code.
So both can't control the same addressed lights.
![Roll Eyes ::)](http://forums.x10.com/Smileys/default/rolleyes.gif)
Side note on the SH624 Security remote.
The Arm Away and Arm Home buttons act differently depending on the Max/Min switch setting.
![whistle :'](http://forums.x10.com/Smileys/default/th_whistle.gif)