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Introduction, Glossary – QSC Audio S series User Manual

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AES3— A digital audio format specification approved by

the Audio Engineering Society and European Broad-

cast Union for inter-device conveyance of a dual-

channel (stereo) digital audio signal. Also called

AES/EBU. This specification is periodically revised

and amendments are published by the AES.

Bundle—The basic network transmission unit under Cobra-

Net. Up to 8 audio channels may be carried in a

bundle. Each bundle is assigned a unique number

and its value denotes the distribution type, either

multicast or unicast, between RAVE devices. A

bundle can be thought of as a virtual cable between

two or more RAVE devices, which transports mul-

tiple audio channels. Bundle numbers can be as-

signed to the RAVE via its front-panel interface or

through an SNMP supporting browser or related ap-

plication.

Channel—A single digital audio signal. Audio channels on

CobraNet have a 48 kHz sampling rate and may

be of 16, 20 or 24-bit resolution. Up to 8 audio

channels may be carried in a bundle.

Conductor—The CobraNet device on the network which sup-

plies the master clock and permissions list. A con-

ductor arbitration procedure insures that there is

one and only one conductor per network at any time.

Crossover cable—An Ethernet patch cable with the transmit

and receive wire pairs swapped at one end. Cross-

over cables permit a direct connection of two nodes

without a repeater or switch in between. A cross-

over cable can also be used for cascading repeat-

ers or switches that don’t have an available uplink

port.

INTRODUCTION:

Glossary

Latency—The time interval from when an event occurs and

when it is perceived. In digital audio routing, this is

typically the time required to convert an analog in-

put to a digital signal, transmit that signal over the

network, receive it and convert it back to analog for

the end listening device. Latency is dependant upon

every device in the signal chain that adds any time

delay to the delivery of the audio.

Management Interface—The management interface (MI) can

be thought of as the software and front panel con-

trols that determine how the RAVE will operate. The

MI is the means for control and monitoring of

CobraNet parameters within the RAVE unit. Two

main management methods are supported by

CobraNet; the host management interface (HMI)

and SNMP. RAVE supports SNMP and its front panel

switches for control. A RAVE unit can use its front-

panel thumbwheel switches to access most con-

figuration parameters for stand-alone mode. The

front-panel interface will satisfy most configuration

requirements. All of RAVE’s configuration param-

eters are accessible using SNMP.

MI Variable Set— The MI variable set is the group of param-

eters that can be controlled by the MI.

Multicast Bundle—A multicast bundle supports a one-to-

many routing of audio on the network. Ethernet

multicast addressing is used to deliver a multicast

bundle. Because a multicast bundle consumes band-

width network-wide (within the same broadcast do-

main), use of this delivery service must be rationed

on a switched network. By design, all bundles on a

repeater network are of the multicast type.