Thanks for the reply...
In my manual, Figure 12 shows an interior siren with a separate tamper zone, as you say. I'm actually looking at Figure 11, which is an exterior siren without a tamper switch. The EOL resistor is shown across the OUT1 and GND terminals.
In case it's helpful, I placed an exact copy of the manual I'm looking at here:
http://www.kroptech.com/~adk0212/Concord4-Install.pdf