VESDA VFT-15 Product Guide
VESDA by Xtralis
58
www.xtralis.com
Network Termination
Terminate the network with 120 Ω resister at both the start and end of the network as shown in the following
diagram.
A. RS232 / RS485 Converter
B. Bias Jumpers Required
Figure D-4: Termination of RS485 network
Bias Jumpers (CN13)
For the first and last detector on the RS485 network the jumpers should be 1-2 and 4-5 to bias the
transmit/receive lines. For all other detectors all the jumpers should be removed.
A. Connect jumpers 1-2 and 4-
5 only for the first or last
detector
B. Do not use this connector
Figure D-5: Bias jumpers on detectors.
D.4
Installation Guide for RS485 Equipment
Communications to RS485 standard are designed to reject a degree of interference, but care must still be
taken when designing and implementing the installation to minimize the level of interference imposed on the
equipment. To prevent damage due to tropical storms and other sources of large external currents and
voltages, additional surge absorbing components may be required as part of the installation.