Distech Controls ECL/ECB-PTU Series - About Setting Built-In EOL Terminations; Only a Daisy-Chained Data Bus Topology Is Acceptable

22 Network Guide
About Setting Built-in EOL Terminations
ECB-PTU Series Line-Powered Controllers use DIP switches (found alongside those DIP
switches used to set the MAC address) to enable the build-in EOL resistors and biasing cir-
cuitry.
ECB 24V Powered Controllers have built-in EOL terminations. These Controllers use jumpers
to enable the EOL resistors and biasing circuitry.
Refer to the controller's Hardware Installation Guide for how to identify and set a controller's
built-in EOL terminations.
Only a Daisy-Chained Data Bus Topology is Acceptable
Use a daisy-chained BACnet MS/TP data bus topology only. No other data bus topology is
allowed.
Figure 5: Typical BACnet MS/TP LAN Topology Showing How Devices are Daisy-Chained Together to Form One
Data Bus Segment
Only linear, daisy-chained devices provide predictable data bus impedances
required for reliable data bus operation.
Only a daisy-chained data bus topology should be specified during the planning
stages of a project and implemented in the installation phase of the project.
A spur is only permitted when it is connected to the data bus through a repeater
(See Using Repeaters to Extend the Data Bus on page 28.).