How do I wire Class B vs. Class A zone loops on the SK-5207, and what end-of-line resistor value is required?

On the Silent Knight 5207, Class A (Style D) zones (1 and 2) are wired as four-wire circuits and require no end-of-line (EOL) resistor (Page 26) [1].

Class B (Style A) zones (3 through 8) are wired as two-wire circuits and require a 4.7K-ohm EOL resistor, specifically Model 7628, wired in parallel with the contact farthest from the panel (Page 26) [1](Page 15) [1].

Wiring Instructions:

1. Class A (Zones 1-2): Connect as a four-wire loop using normally open contacts; do not use smoke or duct detectors on these zones (Page 26) [1].

2. Class B (Zones 3-8): Connect as a two-wire loop with one side to the zone input and the other to loop power (Page 26) [1].

3. EOL Placement: For Class B, install the 4.7K-ohm resistor in parallel with the last device (Page 26) [1].

4. Loop Resistance: Ensure the maximum resistance does not exceed 30 ohms (Page 26) [1].