Rane NM 48 - Manual (Page 7)

Manual-7
Important Big Picture Concepts
There are several imperative concepts which must be
known to effectively understand the NM 48 and its CobraNet
technology. A few of these are discussed below. Reading the
rest of this manual and a thorough visit to
www.peakaudio.com/cobranet are highly recommended.
NM 48 Memory scheme. All Rane products that contain
Memories, including the NM 48, follow a common scheme:
The LCD display (or software screen for PC-controlled
devices) shows the current settings of the device. Sixteen
Memory locations (or some number, depending on the
product) exist from which the current device settings are
stored and recalled. The current settings are considered
Memory zero; some people like to think of Memory zero as
“working Memory.” All device editing is performed using
Memory zero – even though we never display the number
zero. There are, therefore, actually 17 Memories – 1 through
16 and zero.
Any changes made to the device are immediately stored in
Memory zero. Should there be a power interruption, the
contents of Memory zero are recalled upon power up from
their previous, pre-power-down settings. Thus, work in
progress is never lost and the device comes up with the same
settings with which it went down.
Once you are happy with the current settings in Memory
zero, they can be stored to one of the 16 Memories. To
display or edit a previously stored Memory, recall it into
Memory Zero. See the Memory Edit section on page Manual-
5 for more details.
Control data transmission. In addition to the thousands
of audio Bundles available in CobraNet, additional network
data space is allocated in CobraNet for control data transmis-
sion. This non-Bundle space, if you will, is where the NM 48
transmits the Serial (RS-232) data and Memory data for the
MRP. This control data is transported asynchronously over
CobraNet (not isochronously like the audio data), although
with a theoretical maximum of 9 Mbits/sec there is little need
to worry about control data arrival times. This is only 468
times faster than 19200 serial control data!
CobraNet Bundles. The NM 48 can access up to 999 of
the over 65,000 Bundles available (using Peak Audio’s
CobraCad software, all 65,000 Bundles are accessible).
CobraNet divides the tens of thousands of Bundles into three
different Designations or types for the transport of audio data
over the network. The table on page Manual-9 explains the
differences between the three types of CobraNet Bundles.
There are advantages and disadvantages in using each. The
Network Examples section after the table discusses applica-
tions for the various Designations.
Bundle Transmission conflicts. Do not transmit onto the
same Bundle from two different CobraNet devices. Doing so
causes the loss of the data sent from the second device.
Firmware primer. The NM 48 contains two pieces of
internal firmware. One is the CobraNet firmware for the
CobraNet interface, the second is the NM 48’s own internal
Rane firmware for the front panel interface, et cetera.
The Rane firmware revision number is displayed in the
NM 48 LCD display on the top line during power up. Both
the Rane firmware version (e.g., Version 1.01) and the date
the Rane firmware was compiled (e.g., Mar 21, 2000) is
displayed. Displaying the additional date is a good way to
ensure Y2K compliance. To update the Rane firmware, you
must replace an internal chip.
The CobraNet firmware version is displayed on the bottom
line of the LCD display during power up (e.g., CobraNet rev
2.6.4). Interoperability between various CobraNet devices
requires matching CobraNet firmware versions. CobraNet’s
Disco utility provides the means to download new CobraNet
firmware into the NM 48. You must obtain Disco and the
required binary CobraNet firmware files separately. There is a
unique firmware file for each model of CobraNet device;
contact Rane for the latest CobraNet firmware if needed.
A Note on Network Hardware. Before running out to
your nearest computer retailer for networking equipment,
check out the latest list of equipment blessed by Peak Audio
at www.peakaudio.com/cobranet/tested_products.htm. (As a
note of interest, a look through price lists will show you that
the price of a non-managed switch has come down close to
the price of a repeater hub. You would be wise to spend the
extra bucks and go for the switch, as it will make your
network more flexible and expandable.)
Four basic network hardware devices exist for use in
CobraNet network designs. The simplest, least expensive and
previously most common are called repeater hubs, which
send all incoming data out all of their network ports. Thus
repeater hubs are always multicast (broadcast) devices – all
data goes everywhere. Use repeater hubs only when you have
a dedicated CobraNet network (no computers) and when all
audio channels are needed at all CobraNet node locations. If,
for audio security or other reasons, your application requires
certain channels to be accessible only in a certain area of the
network, you cannot use repeater hubs (use switched hubs).
Also you cannot use repeater hubs in your network if you
need to share computer data and CobraNet data on the same
network. Repeater hubs are devices for freshmen, Network
101 designs. As with many technologies, repeater hubs have
had their day and may soon be a thing of the past.
The second kind of network hardware devices are called
switched hubs which are only a little bit more expensive than
repeater hubs. Using switches for your network greatly
increases the efficiency of the network and allows computer
data to be shared on the network. Switches automatically
“view” the IP address (destination) of all incoming data and
only send the data out the single required port for delivery,
therefore, switches are unicast (point-to-point) devices.
Switches are the more common network hardware devices
used for CobraNet networks. Switched hubs are like the
Junior or Senior class of the network world.
A third type of network hardware is a managed switch.
Similar to a switch – but the next step up the rung – managed
switches can be user-configured in several ways: you can
create Virtual LANs (VLANs) and change the network
architecture among various VLAN setups; you can set the
managed switch up to prioritize the incoming data so audio
data has higher priority than computer data, for example.
With such capabilities, you can see that managed switches are