IQ-PIP-USP2/CN
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IQ-PIP-USP2/CN Reference Manual
ing information. The “beat” also
includes information as to which
addresses can transmit at certain
time slots within the “beat” period.
The Conductor regulates the
CobraNet digital audio traffic on the
CobraNet network. Each transmitter
is given a “permission” to transmit in
a given time-slot within the Conduc-
tor controlled isochronous cycle-
time. The time-slot is determined by
the assigned bundle priority. Higher
bundle priorities receive lower-num-
bered positions and are transmitted
first. The “Receiver Count” monitor
indicates how many devices are
recieving the digital audio bundle.
The “Active” indicator indicates
whether the particular Bundle is
being actively transmitted onto the
network.
10.4.4 Bundles and Audio
Channels
All audio channels are packaged
into groups called Bundles (formerly
called Network Channels) for trans-
mission over the Ethernet network.
Each CobraNet device has the abil-
ity to send and receive a fixed num-
ber of Bundles. The Bundle number
tells the CobraNet conductor which
specific CobraNet device is trying
to communicate with which other
CobraNet device(s) over the net-
work. A given Bundle may have only
one transmitter that places it onto
the network. Unicast Bundles may
have only a single receiver. Multicast
Bundles may have multiple receiv-
ers.
Bundles from 1 to 255 are desig-
nated as “multi-cast” Bundles. This
means that they are transmitted to
multiple receivers. This type is most
used on “repeater” networks limited
to 64 channels.
Bundles from 256 to 65,279 are “uni-
cast”. This means that they are trans-
mitted to one and only one receiver.
This type is most used on “switched”
networks requiring more than 64
channels.
A Bundle can carry up to 8 audio
channels (see the block diagram in
Section 10.10). The usual assign-
ment is 8 channels at 20 bits. Using
less audio channels is possible but
maximum size bundles are sug-
gested for most efficient utilization
of network bandwidth. If 24 bit data
is desired, then only 7 audio chan-
nels can be loaded into a single
Bundle.
10.4.5 Repeater Networks
CobraNet can operate on “repeater”
networks and more complex
“switched” networks. Repeater net-
works use low-cost Ethernet hubs.*
On this type of an Ethernet network,
all packets are broadcast to all con-
nected nodes. CobraNet multi-cast
and uni-cast Bundles can be as-
signed but because of the simpler
repeater-type hubs, even uni-cast
transmissions are broadcast to all
nodes. Therefore, a maximum of 8
full-loaded Bundles (64 audio chan-
nels) are allowed on the entire net-
work. More Bundles may be allowed
if they are loaded with less than the
full eight audio channels. There is
no limit to the number of active re-
ceivers on a repeater network. Gen-
erally, a repeater based CobraNet
* See Tested Ethernet Products on the
Peak Audio website for a list of recom-
mended Ethernet repeaters.
