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8. DO NOT connect modules or clusters in a “stub” fashion.
This means do not connect a branch cable off an EIA-485 cable to run to a module 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.
8.3.2 TERMINATION NOTES:
1. The DSAi Terminate Switch connects a 120 ohm resistor as a load on the EIA-485 cabling.
2. Normally, USB to EIA-485 or RS-232 to EIA-485 converters also have a termination resistor connected
as a load on the computer end of the EIA-485 cabling. If optional, this termination should be switched on.
Both this termination resistor and the one in the module at the far end of the EIA-485 cabling from the
computer are required to ensure proper network operation.
3. Due to inherent current limitations, the load resistance on EIA-485 hardware must be greater than 50
ohm. This means only ONE module Terminate Switch can be “ON” on the EIA-485 network along with
the converter’s termination resistor. If more than one module Terminate Switch is “ON”, the network can
experience intermittent or non-existent communications. Additional terminations needlessly draw more
power from the RS-485 converters, reducing signal strength.
4. The Terminate Switch only works for the EIA-485 cable connection at the Phoenix Contact connector.
The Terminate Switch does not work for EIA-485 connections between modules using the Signal Link
connectors. Therefore, use the Terminate Switch only on the module within a cluster that is connected
to the network via the Phoenix connector.
8.4 Support For Ethernet
The infrastructure for a CobraNet network must be designed and built using standard IEEE 802.3u 100BASE-T
Ethernet network hardware. As this is a standardized technology, EAW does not provide technical support for
Ethernet networking. Standards and technical documentation for the design, set-up, operation, and troubleshooting
of 100BASE-T Ethernet networks are available from a variety of sources on the Internet.
8.5 Support For CobraNet
CobraNet technology relies on specific and exacting network timing issues to deliver digital audio to its
destination intact and with no dropouts. As such, there are certain limitations to how an Ethernet network for
CobraNet can be designed. DSAi requires that CobraNet be set to use multicast bundles. For specific
information about designing a CobraNet-compliant network, contact:
Peak Audio (A Division of Cirrus Logic)
305 Interlocken Parkway
Broomfield, CO 80021-3484
Phone: 303-466-5228
Fax: 303-464-6776
e-Mail: info@peakaudio.com
Web: http://www.peakaudio.com
NOTE: Peak Audio’s web site provides, on-line information about designing an Ethernet network that
complies with CobraNet requirements. It also provides links to information about Ethernet technology.
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