Disclaimer: This is based on a VERY quick look in a coffee break, so no guarantees!
I'm assuming that what you want to do is connect two switches to one controlIer, with each switch as shown in section 11.5. If I'm reading this right, all that happens when the call happens is:
- C connects to N/O,
- which switches the trigger resistor in parallel with the EOL resistor,
- so the resistance between Line in + and Line in - drops from 1.5K to 750ohm.
If this is the case the connection to N/C is not needed - other than being a convenient place to terminate the wires and resistors. By removing the connection to N/C it looks like you can wire two units in parallel (C to C and N/O to N/O). Then either (or both) will trigger an alarm.
- Line in + connects to EOL resistor and trigger resistor;
- Other end of EOL resistor connects to N/O of both boxes and Line in -;
- Other end of Trigger resistor connects to C of both boxes.
The worse that will happen is that if both alarm at once the resistance between Line in + and Line in - will drop to 500ohm (1.5k / 3).
Hope this helps...
Andy Millar CEng MIET CMgr MCMIhttp://www.linkedin.com/in/millarandy
"The aim of argument, or of discussion, should not be victory, but progress." Joseph Joubert