Honeywell TC49A - Help Identify Function of Wires

Hi All:

Can someone link me to a manual for the Honeywell TC49A alarm? Or does anyone have access to a manual?

I have two in my home I just purchased and would like to replace them. I would like to know what the functions of the 4 different wires are. There are yellow, blue, black and white wires. Looks like the Black and White are mains. What are the yellow and blue for?

Thanks for any help.

I found this information on line from a book. The book is Ciarcia’s Circuit Cellar, Volume 2, By Steve Ciarcia. It covers connecting a smoke detector into a computer to monitor for smoke. It shows the blue and yellow wires used to connect additional normally open heat detectors. I cannot verify the accuracy of this in any way, but here it is.


A commercially available ionization type smoke detector shown in figure 4, has been configured to interface to the computer. The AC powered TC49A by Honeywell is ideally suited for this purpose, since it is designed for parallel attachment to other sensors. In this instance any number of normally open temperature sensors can be attached between the blue and yellow output leads of the device. Should any of these sensors or the smoke detector itself detect an alarm condition, the 35 V normally present on these wires will drop to 2 V. The relay which had previously been in an energized state will open, signaling the event to the computer. In any case it is always a good idea to have a battery powered smoke detector also within the residence.