Help Identify Part

Purchased an OEM radio for 98 Civic LX from ebay recently identical to
the link below:

http://tinyurl.com/lqbn8

Can you help identify the part viewed from the picture of the backside
of the radio..It shows a green connector with a black circle to the left
of it..

The tag on the part identifies it as a "Security Control Main Unit" with
a slide switch for either Cx/Dx or Hx/Lx/Ex..

My FSM doesn't indicate what this is for .

What is it and what is its' function?

Thanks,

Rich

 

It is the Honda accessory security system. A dealer installed option from
Honda.

 

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That is SO COOL! I have one of those radios (without the alarm system)
and wondered why it was shaped with that groove in the top.

That's a great find.

'Curly'