User`s manual

Alcorn McBride Digital Video Machine DVM-7400 User’s Manual Rev 1.5
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Hardware
Ethernet hardware typically uses an eight-wire (four pair) cable that makes a
point-to-point electrical connection. When connected to a switch, an Ethernet
device is able to communicate with many other devices using the same
connection. Do not let that idea bother you because setting up a small network to
control your show will be easier than you think.
Network Equipment
Now a few words on what the difference is between systems using the network to
communicate and devices that make up the network. Devices (PCs, controllers,
DVM7400/E, AM4/E, V16Pro and such) are connected to the network so that
they may pass information to each other. In the first example, the network was a
simple point-to-point connection. This is different from a RS232 connection in the
fact that Ethernet requires addressing and controls that go far beyond a simple
dedicated serial connection.
Devices such as hubs, switches and routers make up the network itself. The
purpose of the network is to permit as many devices possible to be connected
together. Just think of how your PC may be connected to the one down the hall or
even to mine way over here or remain connected to mine if I go half way around
the world. When many PCs, show controllers and other network devices all
sending data back and forth, there must be a post office to deliver the mail, so to
speak. All these devices work together to get the mail delivered.
So why do we need hubs, switches, and routers to create an Ethernet network?
There are different reasons to use each of these devices so let’s go over the
basic functions of each one of them. Although small control networks are fast and
easy to implement, the nature of non-dedicated connections can be hard to
manage. As your network grows, it’s sometimes a good idea to maintain a map of
the connections.
Hubs
Hubs have become scarce in modern networks, often being replaced by higher-
performing switches or routers. Hubs copy all traffic to all ports at the same time.
You may however, still find a hub in an existing network or need one for simple
network troubleshooting.
Switches
These devices are similar to hubs except that switches send data only to the port
connected to the device with the corresponding Ethernet address. Much more
traffic can be supported when using switches. If we use the post office example,
you send a card to a friend and it goes only to your friend or if you send multiple
cards they will all go only to the addressed locations and nowhere else. The
Ethernet switch will support as many separate interconnects as it has ports.
Another function of the switch is the ability to store addresses and remember the
ports used to make the connection. This is valuable because it increases the
efficiency of the data transfer. Ethernet switches are best for show control
networks.
Routers
These devices are more complex in that they offer a connection between
networks (such as your home network to the Internet). If you are planning to
control or program your show via a remote Internet, you will need a router. Please
be aware that you may also need an Internet Service Provider (ISP) and network
administrator to maintain the security of your systems.