Vocia supports the transmission and receiving of CobraNet audio from CobraNet enabled devices such as a Biamp Audia Flex CM. Vocia CobraNet Inputs can be used to accept background audio in to the system and CobraNet outputs can be used to output background audio and paging (Pre Vocia signal processing). Vocia devices only support a CobraNet latency of 5 1/3 msec, 20-Bit depth and a 48kHz sample rate so the transmitting or receiving Audia or CobraNet capable device must match these settings. When a new Vocia CobraNet input or output is created the bundle number is statically assigned and cannot be modified. This is done since Vocia uses certain bundles for internal messaging, networking and control. The transmitting or receiving CobraNet device must be configured to the same bundle number allocated by the Vocia system otherwise the devices will not communicate. If using other non-Vocia CobraNet devices configured with explicit bundles on the same CobraNet LAN the Vocia compiler is required to be informed of this in order to calculate the correct Vocia bandwidth limits. The Non-Vocia CobraNet Devices dialog in the Tools Menu should be updated to reflect the network state.
CobraNet Based Inputs can be configured in two places in the Vocia software and operate slightly differently, in the World Properties in order to enable or disable Local Inputs on a Zone basis (multicast bundles that affect the simultaneous Paging capabilities), or in the output device dialog in order to enable or disable CobraNet Based Local Inputs on a per output channel basis (unicast bundles that do not affect the simultaneous Paging capabilities).
A CobraNet Input enabled in the World Properties allows the creation of a new CobraNet multicast audio bundle that can be used as a Background Source by a Vocia System. Each audio bundle can utilize up to 8 channels of audio. Review the Background Audio CobraNet Input section for more details.
A CobraNet Input enabled in any Vocia Audio Output device allows the creation of a new CobraNet unicast audio bundle that can be used as a Background Source on a per channel basis. Review the Local Audio CobraNet Input section for more details.
The use of the Non-Vocia CobraNet Devices dialog is recommended to inform the Vocia compiler when using shared CobraNet resources
To utilize a CobraNet Output from a Vocia system, a VO-4 or VO-4e is required and the output can be enabled in the Configuration & Settings of the VO-4 or VO-4e’s General icon window. This will assign a pre-processing Multi-Unicast bundle number to the device. This can be accepted by up to 4 receivers for use in other CobraNet based systems such as the Biamp Audia platform.
The CobraNet output will include any non-Emergency paging and background audio assigned to the Zone just as it would be heard if listening to the analogue output on the device. The difference is on a VO-4e Emergency paging and messaging is available. The CobraNet output and analogue outputs can both be used in conjunction with one another.
The use of the Non-Vocia CobraNet Devices dialog is recommended to inform the Vocia compiler when using shared CobraNet resources
Vocia also uses CobraNet for its normal Paging and message delivery. The maximum number of Simultaneous Pages available in the system is 30 Pages however any enabled CobraNet Input or Output bundles reduces the available network bandwidth which in turn affects the number of Simultaneous Pages available in the local World. The total number of Simultaneous Pages available to the system is shown as part of the Validation and Compilation Results.
Although not technically necessary, if other CobraNet devices are transmitting multicast bundles on the same Network, even if not being used by Vocia, these still affect the available network bandwidth and will impact the amount of Simultaneous Pages available. In order for the Vocia Compiler to account for these additional network resources, it’s recommended to add them to .
CobraNet traffic should be physically separated from regular Ethernet communications given that CobraNet uses broadcast transmissions which are resource intensive. When designing or assessing whether existing network infrastructure will be satisfactory for a Vocia system there’s some specific points to be considered.
Vocia (and CobraNet) devices only support 100Mbit Ethernet connections however the increased network traffic caused by a large amount of point to point traffic necessitates that suitably capable switch infrastructure is used in order to guarantee correct network operation. In order to support the increased network traffic that this feature makes possible, the network used in a Vocia World that supports this feature must use switches with a gigabit backplane and inter-switch communication must occur using gigabit uplink ports
If sharing Ethernet and CobraNet traffic on the same switch (not ‘hubs’), the Ethernet switches should be of the 'managed layer 2' type. Managed switches offer several advantages including the ability to segregate switch ports into Virtual LAN’s (VLAN). In addition, they offer Spanning Tree Protocol (STP) which is used for creating redundant network links, as well as Trunking to increase network bandwidth.
Another important point to consider is that CobraNet uses Layer 2 technology and is therefore non-routable. This means all Vocia devices within a Vocia World are required to be on the same network subnet otherwise they will not be able to communicate or share digital audio with each other.
Since CobraNet uses Ethernet cabling there is a limit of 300ft (100 meters) between each Ethernet switch and device. However, fiber-optic cable may be used to extend this distance limitation. Fiber-optic cable can be used with switches that have fiber-optic ports, or media converters can be used to interface fiber-optic cable with standard RJ-45 ports.
Additional information regarding CobraNet compliant network topologies and protocols can be found online at http://www.cobranet.info/support/design/switched_networks.