Ethernet interface

Figure 9.12 Firedamp-proof PC workstation for installation in coat mines. The main components are fitted into a flameproof- d - Group I housing. The interfaces for PC keyboard and mouse are intrinsically safe as well as interfaces for 4-20 mA analogous inputs, RS 485 and FSK-PROFIBUS. An optical-electrical interface (Ethernet 10/100 Mbit) is available additionally.

CPU. A standard Motorola CPU was selected, which works under a powerful real-time, multi-task operating system (VxWorks), and has embedded Ethernet interface. This CPU also features 4 IP slots to which can be plugged ... 

In addition, new Ethernet firewall cards that fit in the slot of an individual computer bundle additional layers of defense (like encryption and permit/deny) for individual computer transmissions to the network interface function. These new cards have only a slightly higher cost than traditional network interface cards. 

Today, coaxial cable with baseband transmission is the most frequently used technique in implementations of LANs, in Ethernet LANs as well as in token ring networks. Transmission rates are mostly between 6 and 16 Mbits/s. Interfacing to coaxial cable is rather simple, especially with Ethernet new nodes can be connected to an existing cable without interrupting the operation of the network. 

Transceivers are used to connect nodes to the various Ethernet media. Transceivers, also known as Media Attachment Units (MAUs), attach to the Ethernet cable and provide an Application User Interface (or AUI) connector for the computer. The AUl connector consists of a 15-pin D-shell type connector, female on the computer side and male on the transceiver side. Virtually all Ethernet-compatible computers provide such an AUI connector. The transceiver is generally attached directly to the computer s AUI connector, or the transceiver may be attached to the computer with a specially shielded AUI cable which must be less than 50 m long. In addition to an AUI connector, many computers also contain a built-in transceiver, allowing them to be connected directly to Ethernet without requiring an external transceiver. 

First, AppleTalk uses a Carrier Sense-Multiple Access with Collision Avoidance (CSMA/CA) technology to put data on the cable. Unlike Ethernet, which uses a CSMA/CD method, this technology uses smart interface cards to detect traffic before it tries to send data. A CSMA/CA card will listen to the wire. If there is no traffic, it will send a small amount of data. If no collisions occur, it will follow that amount of data with the data it wants to transmit. In either case, if a collision does happen, it will back off for a random amount of time and try to transmit again. 

Integrated computers can in turn communicate with mainframe computers. A typical interface implemented in computers is a UART (universal asynchronous receiver and transmitter), which is in turn connected to an RS-232, RS-488, or Ethernet interface to permit interactive communication with other computer systems. The same interface capability permits transmission by modem (modulator-demodulator) over telephone lines. The telephone line may allow the manufacturer s central service department to enhance the ability of the on-site operator to service and repair the analyzer. With a bidirectional interface, it is possible to download from the main LIS computer such data as specimen identification, which governs specimen location in the analyzer s loading zone, and to send test results from the analyzer back to the LIS, either in real time or by batch. 

Ethernet, or optional wireless interface are used for control from a PC and the system can be optionally extended with integrated graphical user interfaces, data analysis, and storage for stand-alone instrument use. The Corn-Interface allows for fiiU instrument control from Java, C, Lab View, Matlab, and so on. Additional fast hardware synchronization is possible through several sync in/out ports. 

NAT box A system board with three Ethernet interfaces. It will translate the IP and MAC addresses of the attacker traffic while allowing the authenticated host traffic to pass without any modification. 

To setup the attack, the authorized machine should be disconnected from the switch port protected by 802. IX. Next, the authorized machine should be connected to one of the three Ethernet interfaces of the NAT box and another interface of the box should be connected to the 802.IX protected switch port. Likewise, the attacker computer should be connected to the remaining interface of the NAT box. 

NAT Box ALIX.2C3 System Board with 3 Ethernet interfaces running Linux OpenWrt 2.6.22. 

Digital interface some potentiostats feature auxiliary A/D inputs and D/A outputs that can be controlled by the software. These are convenient for controlling auxiliary equipment, such as electromechanical shutters or magnetic stirrers. GPIB used to be the standard interface to the computer for instmment control and data exchange. However, this >30-year-old standard is now outdated and is superseded by USB and/or Ethernet interfaces. The same goes for the even older - and much slower - RS-232 interface. 

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