Telephone wiring and heat detector ???

Hi. I'm am currently living in a house that I do not own. In the kitchen, on one wall fairly close to the ceiling, there is a small round device that is labeled "heat detector." Today I looked inside the heat detector and noticed that instead of operating on a battery or being hard-wired to the electricity, it is wired to the telephone line. Does this make sense? It is an older-type telephone line consisting of red, green, yellow and black wires; however, instead of each color wire being connected to one of four different terminals, as would be the case on a phone jack, the red and yellow wires were wound around each other and were connected to one terminal, and the black and green wires were wound around each other and connected to a second screw/terminal. The other two screws were empty (no more wires to attach to them). Can someone explain this to me? Thank you.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
It is probably hooked up to an alarm panel. It is very common for those devices to use the same kind of wiring for a telephone. As far as the other 2 screws not being used, I think you can wire some heat sensores as 2 wire or 4 wire, depending on what kind of application is its used for.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.