Author: Neftaly Malatjie

Like twisted pair cable, coaxial cable or coax cable is another type of copper cable which has an inner conductor surrounded by a foam insulation, symmetrically wrapped by a woven braided metal shield, then covered by in a plastic jacket (as shown in the following image). This special design allows coaxial cable runs to be installed next to metal objects such as gutters without the power losses that occur in other types of transmission lines. Coaxial cable acts as a high-frequency transmission cable while contains a single solid-copper core, and compared to twisted pair cable, it has over 80 times the transmission capability. This kind of cable is mainly adopted in feedlines connecting radio transmitters and receivers with their antennas, computer network connections, digital audio (S/PDIF), and distributing cable television signals. 75 ohm coaxial cable and 50 ohm coaxial cable are two coaxial cable types. 75 ohm cable aims to transmit a video signal, while the 50 ohm cable is designed to transmit data signals in a two-way communication system.

Pros: Coaxial cable can be installed easily, relatively resistant to interference.

Cons: It is bulky and just ideal for short distance transmission.

Twisted pair cable is a type of ordinary wiring which connects home and many business computers to the telephone company. It is made by putting two separate insulated wires together in a twisted pattern and running them parallel to each other which helps to reduce crosstalk or electromagnetic induction between pairs of wires. Twisted pair cable is good for transferring balanced differential signals. The practice of transmitting signals differentially dates back to the early days of telegraph and radio. The advantages of improved signal-to-noise ratio, crosstalk, and ground bounce that balanced signal transmission brings are particularly valuable in wide bandwidth and high fidelity systems.

According to whether the cable has a shielding layer, there are two common types of twisted pair cables—shielded twisted pair (STP) cable and unshielded twisted pair (UTP) cable. STP cable is available for Token Ring networks, while the UTP cable is more suitable for Ethernet networks. The most common UTP cable types applied in Ethernet network are cat5e, cat6a and cat7 cables, etc. The following image shows the different structure of UTP and STP cables.

Pros: Twisted pair cable is more flexible and cheaper than coaxial cable and fiber optic cable, and it is easy to install and operate.

Cons: It encounters attenuation problem and offers relatively low bandwidth. Besides, it is susceptible to interference and noises.

As we all know, in every communication system, all the sending and receiving devices, like fiber optic switch, need to adopt massive bundles of wires or cables to achieve connections for data transfer. Nowadays, the most common cable types used in communication systems are twisted pair cable, coaxial cable and fiber optic cable. With these three cable types equally deployed in network communication, people may feel confused which one is the ideal choice for their networks? This article aims to introduce some differences among twisted pair cable, coaxial cable and fiber optic cable and to tell you how to distinct them from each other in terms of features and specifications as well.

The following are the WAN protocols;

SNA

Systems Network Architecture (SNA) is a data communication architecture established by IBM to specify common conventions for communication among the wide array of IBM hardware and software data communication products and other platforms. Among the platforms that implement SNA in addition to mainframes are IBM’s Communications Server on Windows, AIX, and Linux, Microsoft’s Host Integration Server (HIS) for Windows, and many more.

The way in which products internally implement these common conventions can differ from one product to another, but because the external interface of each implementation is compatible, different products can communicate without the need to distinguish among the many possible product implementations.

SNA products recognize and recover from loss of data during transmission, use flow control procedures to prevent data overrun and avoid network congestion, identify failures quickly, and recover from many errors with minimal involvement of network users. SNA products also increase network availability through options such as the extended recovery facility, backup host, alternative routing capability, and maintenance and recovery procedures integrated into workstations, modems, and controllers.

TCP

TCP/IP is a communication protocol used between physically separated computer systems. TCP/IP can be implemented on a wide variety of physical networks.

TCP/IP is a large family of protocols that is named after its two most important members, Transmission Control Protocol and Internet Protocol. Figure 1 shows the TCP/IP protocols used by CICS® ONC RPC in terms of the layered Open Systems Interconnection (OSI) model. For CICS users, who may be more accustomed to SNA, the left side of Figure 1 shows the SNA layers that correspond very roughly to the OSI layers.

Figure 1. TCP/IP protocols compared to the OSI and SNA models

Hub is a device that splits a network connection into multiple computers. It is like a distribution centre. When a computer request information from a network or a specific computer, it sends the request to the hub through a cable. The hub will receive the request and transmit it to the entire network. Each computer in the network should then figure out whether the broadcast data is for them or not.

Currently Hubs are becoming obsolete and replaced by more advanced communication devices such as Switchs and Routers.