Honeywell Silent Knight IFP-2000 Module 3 Installation Manual page 57

2 Wire Smoke Class B Wiring 2 Wire Smoke Class B Wiring
Any compatible U.L. listed two-wire smoke
detector can be used with the control panel
See appendix A
for compatible devices for compatible devices
NOTE: O is positive,
X is negative
Flexput™ I/O Circuits Flexput ™ I/O Circuits
2 wire smoke
detectors