Honeywell SDC Service Manual page 19

SDC / DHC
EN2H-0221GE51 R0812
With star-topology data bus systems, double earth connections
may not be made. The earth connection must be made on one
side of the star!
a Shielding
c Distributor terminal
The outside sensor may not be installed near transmitters or
receivers (e.g. on garage walls near garage door opener
receivers, amateur radio antennas, radio alarm systems or directly
next to large transmission equipment etc.).
b Two-lead data bus line
d Branch box
Safety instructions
19