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8.3 EIA-485 Network
EIA-485 network cabling has certain limitations that these notes
summarize. Improper set-up of an EIA-485 network can result in faulty or
no operation. To use EIA-485 network configurations or cabling schemes
not addressed in this manual, consult a qualified network professional.
8.3.1 CABLING NOTES:
1. Single Loudspeaker or loudspeaker cluster:
One end of the EIA-485 cable is connected to the computer’s EIA-
485 port and the other to the EIA-485 connector on the loudspeaker
or on one of the loudspeakers in a cluster.
2. Multiple Loudspeakers:
One end of the EIA-485 cable is connected to the computer’s EIA-
485 port. The cable is then connected daisy-chain fashion to multiple
loudspeakers or clusters. This means to connect the EIA-485 cable
from the computer to a loudspeaker or cluster, then to loop it to add-
itional loudspeakers or clusters. Use the supplied RJ-45 Signal Link
Cables to link loudspeakers within a cluster using the Signal Link jacks.
This cable also interconnects the audio between the loudspeakers.
3. DO use an EIA-485 hub when separate EIA-485 home runs to the
computer are needed because of cable routing constraints. Note:
EIA-485 hubs often contain an RS-232 to EIA-485 converter.
4. DO use an EIA-485 hub to extend the length of the EIA-485 cabling
beyond 1000 ft / 300 m. Literature about EIA-485 claims maximum
cable lengths of 4,000 ft. However, the fastest data rates for a DSA
network, assuming ideal network conditions, limit the maximum
to 2,800 ft / 850 m. Performance variations for the network cable,
connectors, EIA-485 drivers, and several other variables can and
often do further reduce this length. Therefore, this is the maximum
recommended length to ensure reliable communications.
5. DO use an EIA-485 hub to connect the EIA-485 network to more
than 31 DSA Clusters. Each loudspeaker within a multi loudspeaker
DSA Cluster counts as one DSA Cluster if they are all connected
DIRECTLY to the EIA-485 network using the EIA-485 Phoenix
connectors. If the loudspeakers within a multi-loudspeaker DSA
Cluster are inter-connected via the Signal Link connectors, and
thus only one is connected directly to the EIA-485 network, then
this counts as only one DSA cluster.
6. DO NOT connect the EIA-485 cabling to the loudspeakers in a star
fashion. This means do not home-run an EIA-485 cable from each
loudspeaker or cluster to the computer.
7. DO NOT connect the EIA-485 cabling between loudspeakers in a
star fashion. This means do not run an EIA-485 cable from one
loudspeaker or cluster to more than one other loudspeaker or cluster.
8. DO NOT connect loudspeakers or clusters in a “stub” fashion. This
means do not connect a branch cable off an EIA-485 cable to run to
a loudspeaker or cluster.
9. DO NOT connect the far end of the EIA-485 cable back to the
computer. This means do not make an electrically closed loop for
the EIA-485 cabling.