SymNet ExpressCobra Series, Quick Start Manual

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10
Quick Start Guide
Remote ARCs
The ARC ports distribute power and RS-485 data to one or
more ARCs arranged in one or more chains over standard
CAT5 cable. The Express Cobra can support up to two
(2) ARCs total within the guidelines set forth in the ARC
Network Design section. (Please see the SymNet Designer
online help for information on how to program the ARC.)
WARNING: The RJ-45 connectors labeled “ARC”
are only for use with the ARC series of remotes.
DO NOT plug the ARC connectors on Symetrix
products into any RJ-45 connector labeled
“SYMLINK”, “ETHERNET” or “COBRANET. The “ARC” RJ-
45 connectors on Symetrix products can carry anywhere
from 6 to 24 VDC which can damage SymLink, Ethernet and
CobraNet circuitry.
ARC Network Design
The ARC can be powered two ways: (1) over CAT5 via the RJ-45
“ARC” port on ARC-enabled Symetrix products, or (2) by local 6 to 24
VDC power supplied to the ARC’s terminal block connections.
The ARC’s power requirements vary depending on the
voltage supplied to it. At 15 VDC, it uses approximately
115 mA, while at 6 VDC it uses approximately 300 mA
maximum. As the voltage goes from 15 to 6 VDC, the
current requirement increases accordingly.
ARCs can be daisy-chained and fed power over this daisy-
chain from the ARC port. However, as the length of the
cable increases, so does the resistive line loss, which lowers
the voltage available at each subsequent ARC. The actual
power drain on each output from an ARC port can vary
substantially depending on the number of ARCs and the
distance each of them is separated by. In order to assist
with system design, Symetrix has available a Microsoft Excel
spreadsheet that can help a system designer determine
power requirements based upon cable length, number of
ARCs and the power supply to be used. This spreadsheet
can be downloaded from the SymNet Technical Support
pages at: http://www.SymetrixAudio.com.
The following table gives some indication of cabling
limitations, based on DC power only (the table is only
relevant for the
RJ-45 ARC port on this specific product):
minimum stated distances assume 28 gauge CAT5 cabling,
maximum stated distances assume 24 gauge CAT5 cabling.
If power is not distributed over CAT5, each RS-485 chain
will be limited to 1000 ft in a star network configuration
and 4000 ft in a daisy-chain network configuration. Longer
distances may be possible using third party RS-485
extender products.
Disclaimer: From time to time we test the compatibility of
our own products with those of third parties. While we are
happy to share with our customers the results of our own
studies as well as other possibly unsubstantiated information
regarding these third party products, it is the policy of
Symetrix, Inc. to neither endorse, recommend nor support
products manufactured and/or supplied by third parties.
The responsibility of choosing third party products which
are compatible with Symetrix products rests solely with the
qualified contractor, consultant or system designer.
WARNING: When designing a system, one must be
careful not to double power any ARCs. If all pins on
the CAT5 connections are used, power can travel
over the CAT5 cable and reach any ARC on
that particular chain. So, power over CAT5 could potentially
come from the originating ARC port or from an ARC that is
powered locally and then daisy chained via CAT5 to other
ARCs. In general, it is recommended to use only one type of
connector on the ARCs, either the RJ-45s (with CAT5 cable)
or the terminal blocks
ARC • Network Design • ARC Audio
ARC PORT PINOUT (both Grounds and
Powers required for specified distance)
Pin # Function
1
Audio (+)
2 Audio (-)
3 Common Ground
4 RS-485 Data (A)
5 RS-485 Data (B)
6 Common Ground
7 Power (+V)
8 Power (+V)
Note: The ARC Audio lines may be grounded at the Symetrix Rack-mount
device and the ARC wall panel to provide additional distance.
CABLE LENGTH LIMITATIONS FOR ARC
DC POWER OVER CAT5 CABLE
Maximum total cable
length(to end of chain)
Number of ARCs in
1 daisy-chain
699 ft. 2
1396 ft. 1