FAQ

Frequent Questions and Answers

We are continuously asked questions about different aspects of Structured Cabling. See below for some of those most frequently asked.


Q.	*What is a Structured Cabling System?*
A.	Structured cabling is a wiring system that uses low cost cable of small diameter, which is easily maintained and installed, is capable of serving many applications and will facilitate necessary shifts and moves of user terminals and equipment. It also needs to conform to the appropriate industry standards, support multiple vendors, product ranges and different protocol options. A Structured Cabling system will support voice, data and other multimedia applications. However, an outlet can support only one application type at any one time. Structured Cabling is usually achieved by flood wiring complete floors. ISO 11801 states that 'in many countries two TOs are provided to serve a maximum of 10m² of usable floor space' and connecting these cables to patch panels which provides the essential flexibility of the cabling system.


Q.	*What are the main advantages of choosing a FTP over a UTP System?*
A.	FTP Advantages - Reduces noise induction into other cables and systems - Likely to meet future EMC Regulations FTP Disadvantages - Increased Termination costs - Increased Cabling and Installation Costs UTP Advantages - Reduced Termination Costs - Reduced Cabling and Installation Costs UTP Disadvantages - Potential increase in crosstalk - Concerns over EMC Regulations


Q.	*What are the different classes when referring to ISO/IEC 11801?*
A.	ISO/IEC 11801 defines five classes for link performance: Class A - For speech band and low frequency applications specified to 100kHz (no longer recognised by the ISO) Class B - For medium bit rate data applications specified to 1Mhz (no longer recognised by ISO) Class C - For High bit rate data applications specified to 16Mhz (Category 3) Class D - For very High bit rate applications specified to 100Mhz (Category 5/5e) Class E - Standards for applications specified to 250Mhz (Category 6) Class F - Standards for applications specified to 600Mhz (Category 7) Optical Class - For high and very high bit data rate applications, specified to 10 MHz and above. Generally bandwidth is not a limiting factor in customer premises.


Q.	*What is T568B?*
A.	T568B specifies the electrical characteristics of field testers, test methods and minimum transmission requirements for UTP cabling. The purpose of this standard is to specify transmission performance requirements of the UTP cabling, Connecting hardware and to provide a benchmark by which to verify the performance of an installed circuit (basic link). The T568B is written for unshielded installations, but specifically mentions that it may also be used for shielded links, which meet the requirements of the standard, but excludes any testing of the shield and its effectiveness.


Q.	*What is Ethernet?*
A.	When transmitting a signal, a computer needs a Protocol (language) in order to communicate with other devices. The Internet uses TCP/IP, whereas LAN's (Local Area Networks) tend to use the Ethernet Protocol. Information is sent across the network in 'packets' using the binary language (1's and 0's). In order to send a packet along a copper cable the signal needs to be converted into a voltage pulse (this equates to a 1 in binary being represented by a 1 volt pulse and a 0 being represented by a ½ volt pulse). A computer needs to have a link to other computers before it can send or receive information, and this normally requires the use of 'Active Equipment' such as Hubs or Switches. One Bit = 1 or 0 (Binary Format) Eight Bits = One Byte = A letter, number or symbol One Kilobit = 1000 Bits One Megabit = 1,000,000 Bits The transmission speed of a signal is expressed as bits per second (bps), therefore a 56Kbps modem is capable of 56,000 bits per second (9 thousand bytes). Most modern networks are capable of running at 100Mbps (100,000,000 bits per second, 12.5 million bytes) A category 5E/6 network can run at speeds of up to 1000Mbps (1000,000,000 bits per second 125 million bytes). This is around 17,800 times faster than a 56K modem.


Q.	*What is Fibre Optic cable?*
A.	An Optical Fibre Cable basically consists of a solid rod of pure glass enclosed inside a 'cladding'. The cladding protects the fibre and helps prevent light loss. By sending millions of pulses of light every second, Optical Fibre is capable of transmitting more information, for longer distances, in less time than conventional copper media. It is not affected by electricity, water or radio interference and is not a conductor, therefore is safe to run externally. Optical Fibre is also a very secure media. Optical Fibre is available in two formats: MULTI-MODE (MM): A type of fibre with a comparatively large central core, typically 62.5 or 50 microns, surrounded by a larger outer cladding, typically 125 microns. Most frequently used as a network backbone or to link building or networks. SINGLE-MODE (SM): A type of fibre with a comparatively small central core, typically 8 or 10 microns, surrounded by a larger outer cladding, typically 125 microns. Most commonly, used for long distances and high speeds by national carriers such as BT and CATV franchises.


Q.	What are the Cabling Specifications for Optical Fibre?
A.	Optical Fibre is rated as core and cladding size e.g. 62.5/125 has a core diameter of 62.5 microns and a cladding diameter of 125microns. There are two types of Optical Fibre available for the structured cabling system. Multimode and singlemode. primarily multimode is the preferred fibre due to the use of cheaper LED transmitters but singlemode (as backbone) can be offered as an alternative if very high bandwidth applications are to be used in the future.


Q.	*What are the differences between the switches?*
A.	10Base-T Hubs - 4 in a Network - Must be connected via RJ45 and Twisted Pair -10Mbps Ethernet Network Cards must be installed in each PC, Printer and Server 100Base-TX - 2 in a Network with less than 5m between - Must be connected via RJ45 and Twisted Pair - 100Mbps Ethernet Network Cards must be installed in each PC, Printer and Server Dual Speed - 10/100 means that it can operate at either speed automatically - Cable Monkey has a range of Network Cards, Hubs and Switches that will support both speeds