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1.8.2 Alarm Output Relay
The relay output provides either Normally Open or Normally Closed dry contacts.
Output relay in idle state
1.9 RS-485 KEYBOARD / PTZ INSTALLATION
All functions can be remotely controlled by the EKB-500 universal keyboard. Using the EEPbus protocol, digital video
recorders, keyboards and speed domes can be installed on one single RS-485 bus. One system can be comprised of up to
8 keyboards.
1.9.1 General RS-485 bus installation
The EKB-500 keyboard uses RS-485 simplex wiring; the signal is transferred via a single twisted pair line. CAT5 network
cable is recommended. The UTP version (unshielded) is sufficient for normal applications. A shielded cable should be used
if the installed cables are expected to be highly susceptible to interference.
The number of devices installed in one bus is limited to 32, and the maximum cable length is 3,900 feet. Both of these can
be expanded using a signal distributor EverFocus Model EDA997A (see below).
Both the first and the last device in the series should be terminated with 120 Ohm resistance in order to minimize line
reflections.
RS-485 bus serial wiring
Cable length from box to device („Stubs") has to be limited to 2m using connector boxes.
RS-485 bus serial wiring with connector boxes and connection cable
Direct RS-485 bus star wiring is not supported unless using an EverFocus Model EDA997A (see below).
INCORRECT RS-485 bus star wiring!
An EDA997A RS-485 signal distributor may be used to use a star wiring configuration.
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