Overview
Device Comm Error displays on the keypad. Reports trouble zone 2.
Wiring issue with the devices.
Issue
Device Comm Error displays on the D636 keypad. CS is receiving a Trouble zone 2 signal.
Solution
The devices (D636, D620, D640) have a wiring issue.
All device data wiring should be connected in series.
Example: Data wire out from panel terminal 11 to the first device