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<h1 class="firstHeading">CobraNet Information</h1>
<div id="bodyContent">
<p id="siteSub"> </p>
<p><img src="Cobranet.JPG" alt="image:Cobranet.png" title="image:Cobranet.png" style="border-width: 2px; border-style: solid;
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<p>CobraNet is a widely adopted audio network solution.
<a href="MAINIntroduction.htm">London Architect</a> has
been created to maximise the inclusion of CobraNet devices,
including Crown and other manufacturers, in a single system
design. Peak Audio's CM-1 module has been used within
the <a href="Hardware Devices.html">BLU series processors</a>
to interface with the hardware.</p>
<p> <br>
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<div class="editsection" style="float: right; margin-left: 5px;">
<p> </p>
</div>
<p><a name="Channel_Count" id="Channel_Count"></a></p>
<h2>Channel Count</h2>
<p>As standard, devices within the Soundweb London system
are capable of transmitting and receiving a maximum of
32 channels of CobraNet audio onto and from the network.
This channel count may be reduced if higher sample rates
or lower latencies are required - see Table C. Each <a
href="BLU-80.html">BLU-80</a> and <a href="BLU-32.html">BLU-32</a>
Soundweb London device may transmit and receive four CobraNet
bundles which can carry a maximum of 8 audio channels
at the default setting of 48 kHz, 20 bit.</p>
<div class="editsection" style="float: right; margin-left: 5px;">
<p> </p>
</div>
<p><a name="Bundles" id="Bundles"></a></p>
<h2>Bundles</h2>
<p>Each output bundle may be assigned to be Unicast or
Multicast. A Unicast bundle may have only a single receiving
device and will not be transmitted unless the receiving
device is requesting, enabling destination controlled
routing. A Multicast bundle may have multiple receiving
devices. No more than three Multicast bundles should exist
within the network to maintain a sensible level of network
traffic.</p>
<div class="editsection" style="float: right; margin-left: 5px;">
<p> </p>
</div>
<p><a name="Sample_Rate_and_Bit_Depth" id="Sample_Rate_and_Bit_Depth"></a></p>
<h2>Sample Rate and Bit Depth</h2>
<p>To maximise channel count, the CobraNet network should
be configured to operate at 48kHz. Each bundle can carry
8 channels of audio data at 16 or 20 bit. A maximum of
7 channels will be available if all channels within a
bundle are required to be 24 bit.</p>
<p>The CobraNet network can also be configured to operate
at 96kHz.  It is recommended that CobraNet is not
used on a system where a device in the design has it's
clock synchronised to BNC since the CobraNet clock will
not be synchronised to the word clock and this will compromise
the CobraNet audio.</p>
<div class="editsection" style="float: right; margin-left: 5px;">
<p> </p>
</div>
<p><a name="Latency" id="Latency"></a></p>
<h2>Latency</h2>
<p>Delay is incurred by the buffering of audio data into
Ethernet packets in CobraNet transmitters and receivers.
Additional delay is incurred in analog to digital conversion,
digital to analog conversion and sample rate conversion.
These additional delays are usually only in the order
of dozens of samples and of no consequence. Data on an
Ethernet network travels at the speed of light, and for
long distance runs optical fire connections should be
used. Standard fast Ethernet runs over CAT-5 copper cable
should be up to 100m.</p>
<p>The maximum latency incurred in a CobraNet network is
256 samples (5-1/3ms) per switch or device through which
the audio data must pass. This latency can be reduced
at the expense of CobraNet audio channels transmittable
from device to device and all devices on the network must
be configured to operate at this latency.</p>
<p>A CobraNet network utilising the CM-1 module can make
use of a number of possible latency times and sample rates.
See the <a href="MAINApplication_Preferences.htm">Application
Preferences</a> in the <a href="Tools Menu.html">Tools
Menu</a>.</p>
<p> <span style="font-style: italic;"><br>
Latency against sample rate at 20-bit resolution:</span></p>
<p> </p>
<table class="wikitable" wrapperparagraphselector="P" style="margin-top: 14pt;"
cellspacing="2">
<tr>
<td class="hcp1"><p> </p></td>
<td class="hcp1"><p> </p></td>
<td class="hcp1"><p> </p></td>
<td class="hcp1"><p> </p></td>
</tr>
<tr>
<td class="hcp2"><p class="hcp3"><span class="hcp4">Latency</span></p></td>
<td class="hcp2"><p class="hcp3"><span class="hcp4">Sample
Rate</span></p></td>
<td class="hcp2"><p class="hcp3"><span class="hcp4">Bit
Resolution</span></p></td>
<td class="hcp2"><p class="hcp3"><span class="hcp4">CM-1
Channel Capacity</span></p></td>
</tr>
<tr>
<td class="hcp2"><p class="hcp3">5-1/3ms</p></td>
<td class="hcp2"><p class="hcp3">48kHz</p></td>
<td class="hcp2"><p class="hcp3">20</p></td>
<td class="hcp2"><p class="hcp3">32 In, 32 Out</p></td>
</tr>
<tr>
<td class="hcp2"><p class="hcp3">5-1/3ms</p></td>
<td class="hcp2"><p class="hcp3">96kHz</p></td>
<td class="hcp2"><p class="hcp3">20</p></td>
<td class="hcp2"><p class="hcp3">16 In, 16 Out</p></td>
</tr>
<tr>
<td class="hcp2"><p class="hcp3">2-2/3ms</p></td>
<td class="hcp2"><p class="hcp3">48kHz</p></td>
<td class="hcp2"><p class="hcp3">20</p></td>
<td class="hcp2"><p class="hcp3">32 In, 32 Out</p></td>
</tr>
<tr>
<td class="hcp2"><p class="hcp3">2-2/3ms</p></td>
<td class="hcp2"><p class="hcp3">96kHz</p></td>
<td class="hcp2"><p class="hcp3">20</p></td>
<td class="hcp2"><p class="hcp3">16 In, 16 Out</p></td>
</tr>
<tr>
<td class="hcp2"><p class="hcp3">1-1/3ms</p></td>
<td class="hcp2"><p class="hcp3">48kHz</p></td>
<td class="hcp2"><p class="hcp3">20</p></td>
<td class="hcp2"><p class="hcp3">32 In, 32 Out</p></td>
</tr>
<tr>
<td class="hcp2"><p class="hcp3">1-1/3ms</p></td>
<td class="hcp2"><p class="hcp3">96kHz</p></td>
<td class="hcp2"><p class="hcp3">20</p></td>
<td class="hcp2"><p class="hcp3">16 In, 16 Out</p></td>
</tr>
</table>
<p>For a comprehensive list of latency and how it affects
channel count please refer to the "Impoortant CobraNet
Information" document from the Help menu.</p>
<div class="editsection" style="float: right; margin-left: 5px;">
<p> </p>
</div>
<p><a name="Clock" id="Clock"></a></p>
<h2>Clock</h2>
<p>The CM-1 modules within the devices on the network automatically
negotiate a 'conductor' that generates a master clock
for the network. An LED on the front panel of the BLU-80
and BLU-32 indicates which device contains the conductor.
If the conductor device should fail then the network will
assign the conductor status to another device, this process
takes milliseconds, although audio cannot be passed through
a CobraNet network without a conductor.</p>
<div class="editsection" style="float: right; margin-left: 5px;">
<p> </p>
</div>
<p><a name="Network" id="Network"></a></p>
<h2>Network</h2>
<p>The Soundweb London system requires an Ethernet LAN
backbone for both proprietary system communications/control
and CobraNet audio distribution. Consequently each Soundweb
London processor requires a total of two network ports
for CobraNet audio and one for control. CAT-5 cable should
be employed for connectivity. It is recommended that the
network should be a discrete system for audio and communications
and should not be used for any other network purposes.
Crown Audio amplifiers and other CobraNet devices may
be connected.</p>
<p>CobraNet does not use TCPIP and should happily coexist
on a network running this protocol. CobraNet does not
run successfully over current wireless networks due to
their inability to guarantee real time transmission (as
needed for audio)</p>
<div class="editsection" style="float: right; margin-left: 5px;">
<p> </p>
</div>
<p><a name="Switches_.26_Hubs" id="Switches_.26_Hubs"></a></p>
<h2>Switches & Hubs</h2>
<p>Ethernet repeater hubs are not recommended and may not
be connected into a switched CobraNet network. A network
may consist only of all switches or all repeaters. The
Hewlett Packard ProCurve is the Harman Group recommended
range of Ethernet switches, for more recommendations check
the Peak website. CobraNet currently runs the system at
100BT speed but a gigabit backbone is recommended, particularly
in shared usage systems (although it is recommended to
have a separate network for CobraNet to avoid collisions
and data queuing).</p>
<div class="editsection" style="float: right; margin-left: 5px;">
<p> </p>
</div>
<p><a name="Switch_.E2.80.98hops.E2.80.99" id="Switch_.E2.80.98hops.E2.80.99"></a></p>
<h3>Switch 'hops'</h3>
<p>Where possible, the CobraNet network should not include
more than seven switch hops (seven switches between transmitting
and receiving Soundweb London devices). An additional
256 sample latency will be induced for each subsequent
switch hop. To combat this, a gigabit Ethernet backbone
should be employed which will increase the number of switch
hops before additional latency occurs.</p>
<div class="editsection" style="float: right; margin-left: 5px;">
<p> </p>
</div>
<p><a name="CM-1_RJ45_LED_Flash_Codes" id="CM-1_RJ45_LED_Flash_Codes"></a></p>
<h2>CM-1 RJ45 LED Flash Codes</h2>
<p>Each CM-1 card has two RJ45 network ports labled Primary
and Secondary. These ports each have two LED indicators
that will flash to indicate the status of the port. Here
are the flash codes for these ports:</p>
<table wrapperparagraphselector="P" style="-moz-background-clip: -moz-initial;
-moz-background-origin: -moz-initial; -moz-background-inline-policy: -moz-initial;
margin-top: 14pt; background-repeat: repeat; background-position: 0% 0%;
background-attachment: scroll; border-collapse: separate;
border-collapse: separate;" cellspacing="2" bgcolor="#F0F0F0"
border="1">
<tr>
<td class="hcp1"><p> </p></td>
<td class="hcp1"><p> </p></td>
<td class="hcp1"><p> </p></td>
</tr>
<tr>
<td class="hcp2"><p> </p></td>
<td class="hcp2"><p class="hcp3"><span class="hcp4">Left
LED</span></p></td>
<td class="hcp2"><p class="hcp3"><span class="hcp4">Right
LED</span></p></td>
</tr>
<tr>
<td class="hcp2"><p class="hcp3"><span class="hcp4">Conductor</span></p></td>
<td class="hcp2"><p class="hcp3">Flashing Orange</p></td>
<td class="hcp2"><p class="hcp3">Flashing Green</p></td>
</tr>
<tr>
<td class="hcp2"><p class="hcp3"><span class="hcp4">Performer</span></p></td>
<td class="hcp2"><p class="hcp3">Solid Orange</p></td>
<td class="hcp2"><p class="hcp3">Flashing Green</p></td>
</tr>
<tr>
<td class="hcp2"><p class="hcp3"><span class="hcp4">Fault</span></p></td>
<td class="hcp2"><p class="hcp3">Flashing Orange</p></td>
<td class="hcp2"><p class="hcp3">Flashing Orange</p></td>
</tr>
</table>
<div class="editsection" style="float: right; margin-left: 5px;">
<p> </p>
</div>
<p><a name="Redundancy" id="Redundancy"></a></p>
<h2>Redundancy</h2>
<p>The CobraNet compatible devices within the Soundweb
London system are fitted with a Peak Audio/Cirrus Logic
CobraNet CM-1 module. The module itself offers a Primary
and a Secondary CobraNet port. Under normal operation
the Primary port only receives audio data from and transmits
audio data to the network. Should the Primary port or
connection fail, the CM-1 module automatically switches
to receive from and transmit with the Secondary port.
This must be considered in network design. It may be appropriate
to connect the Primary CobraNet port to a Primary network
and the Secondary CobraNet port to a Secondary, backup
network. In this event, it should be noted that the backup
network should in some way be bridged to the Primary network
in order for the audio data to be present on the Secondary
network should the module switch over.</p>
<div class="editsection" style="float: right; margin-left: 5px;">
<p> </p>
</div>
<p><a name="Communications" id="Communications"></a></p>
<h2>Communications</h2>
<p>Third party controllers may be connected into the system
via the serial port using the raw message protocol.</p>
<div class="editsection" style="float: right; margin-left: 5px;">
<p> </p>
</div>
<p><a name="Video" id="Video"></a></p>
<h2>Video</h2>
<p>CobraNet, at the time of writing, is not yet capable
of delivering video, although this functionality is being
developed.</p>
<div class="editsection" style="float: right; margin-left: 5px;">
<p> </p>
</div>
<p><a name="CM1_DSP" id="CM1_DSP"></a></p>
<h2>CM1 DSP</h2>
<p>The CM1 CobraNet interface card has onboard DSP used
to perform various functions. CobraNet latency, bit depth,
sample rate and total number of audio channels transmitted
or received can increase the CM1 DSP usage. When trouble
shooting CobraNet problems, make sure you are not exceeding
100% usage on the CM1 DSP meter. This meter can be found
in the Default Control Panel for each London CobraNet
device (BLU-80, BLU-32, BLU-800 & BLU320).</p>
<div class="editsection" style="float: right; margin-left: 5px;">
<p> </p>
</div>
<p><a name="CM1_Meters" id="CM1_Meters"></a></p>
<h2>CM1 Meters</h2>
<p>To conserve valuable DSP resources on the CM1 card,
the CobraNet meters on the transmit and receive bundles
are turned off by default. These can be turned on to aid
in trouble shooting CobraNet, but should not be left on
unless the DSP usage on the CM1 can support the current
design without exceeding 100% usage.</p>
<p>To turn the CM1 meters on:</p>
<ol>
<li class="p"><p class="hcp3">In Design
Mode, highlight the London CobraNet device in the
Main Layout Window.</p></li>
<li class="p"><p class="hcp3">Open the
Properties Window.</p></li>
<li class="p"><p class="hcp3">Expand the
Parameters section.</p></li>
<li class="p"><p class="hcp3">Change the
value of CobraNet Meters to ON.</p></li>
<li class="p"><p class="hcp3">Go Online
with the system.</p></li>
<li>Choose Send Values to Network Device from the Parameter
Synchronization dialog.</li>
</ol>
</div>
</div>
</div>
</div>
<p class="hcp3"> </p>
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