Crown PIP-LITE, Справочное руководство

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page 51
Reference Manual
Networked PIP Series
The usual assignment is 8 channels at 20 bits. You can use fewer channels per bundle, but
maximum size bundles are suggested for the most efficient use of network bandwidth. If 24-
bit data is desired, then only 7 audio channels can be loaded into a single Bundle.
In IQwic, you create audio connections between sending devices (transmitters) and receiv-
ing devices (receivers). For example, a mixer could be a transmitter, and a power amp could
be a receiver.
You assign each connection a Bundle number. The Bundle number indicates which devices
are communicating with each other.
Also in IQwic or System Architect, you address each connection as Multicast or Unicast. A
Multicast (Broadcast) connection is from one transmitter to multiple receivers. A Unicast
connection is from one transmitter to one receiver. For example, if you send a mixer's digi-
tal audio signal to several power amps, the signal would be Multicast. Unicast is most used
on “switched” networks requiring more than 64 channels.
You specify a connection as Multicast or Unicast by the delivery address it you give it in
IQwic or System Architect. 255 and lower is Multicast (Broadcast); 256 and up is Unicast.
6.3.4 The Conductor
A CobraNet system is coordinated by one audio device in the network called the Conductor.
It regulates the CobraNet digital audio traffic on the CobraNet network. That is, the Conduc-
tor is the master clock for the rest of the network.
You choose one device to be the network conductor based on a priority scheme. The Con-
ductor indicator will light on the CobraNet device that is serving as the conductor.
The Conductor handles time-division multiplexing and clock recovery on the network. The
Conductor periodically broadcasts a well-defined “beat” packet to all components to
recover synchronous timing information. The “beat” also specifies which addresses can
transmit at certain time slots within the “beat” period.
Each transmitting device is allowed to transmit in a given time-slot within the Conductor-
controlled isochronous cycle time. The time-slot is determined by the assigned bundle pri-
ority. Higher bundle priorities receive lower-numbered positions and are transmitted first.
6.3.5 Repeater Networks
CobraNet can operate on repeater networks or switched networks. Repeater networks use
low-cost Ethernet hubs. Switched networks use network switches.
Hubs send all data packets to all connected nodes. That is, all devices in the network
receive data -- even the Unicast data. Switches send specific packets to specific devices.
Up to 8 full-loaded Bundles (64 audio channels) are allowed on a repeater network. More
Bundles may be allowed if they are loaded with less than the full eight audio channels.
Generally, a repeater-based CobraNet network must carry only CobraNet data to guarantee
reliable transmission of audio packets. Use of repeater networks is not recommended.