by Dinesh Thakur Category: Multiple Access

Telephone line or telephone circuit (or just line or circuit within the industry) is a single-user circuit on a telephone communication system. Typically this refers to the physical wire or other signaling medium connecting the user's telephone apparatus to the telecommunications network, and usually also implies a single telephone number for billing purposes reserved for that user.

 
by Dinesh Thakur Category: Multiple Access

In case of TDM, time slots are allocated to channels, even if they have no information to transmit. This is just wastage of the bandwidth and to overcome this inefficiency of standard TDM, a technique known as STDM has been developed where time is allocated to lines only when it is required. This is achieved with the use of intelligent devices that are capable of identifying when a terminal is idle.



 
by Dinesh Thakur Category: Multiple Access

In the 1970s, the Department of Defense, or DOD (Department Of Defense), decided before the proliferation of machines using different, incompatible communication protocols, to define its own architecture. This architecture, called TCP / IP, is the source of the Internet. It is also adopted by many private networks, called intranets.



 
by Dinesh Thakur Category: Multiple Access

• In TDMA, the bandwidth of channel is dividend amongst various stations on the basis of time.

• Each station is allocated a time slot during which it can sent its data i.e. each station can transmit its data in its allocated time slot only.

 
by Dinesh Thakur Category: Multiple Access

For digital sources, two alternative technologies have evolved for multiplexing. These are Time Division Multiplexing (TDM) and Code division Multiplexing (CDM). TDM provides a way to merge data from several sources into a single channel for communication over telephone lines, a microwave system or a satellite system. TDM can be implemented in two ways. These are synchronous TDM and asynchronous TDM. Asynchronous TDM is popularly known as Statistical TDM.

 
by Dinesh Thakur Category: Multiple Access

In Frequency Division Multiplexing (FDM), multiple channels are combined onto a single aggregate signal for transmission. The channels are separated in the aggregate by their frequency. It is explained in the Figure where a frequency dimension is subdivided into several non-overlapping frequency bands. Each channel ci is allotted its own frequency band as depicted in Figure.

 
by Dinesh Thakur Category: Multiple Access

Data encapsulation simply means adding the IP header to the data. The IP header consists of five or six 32-bit words; the sixth word is attributed to the IP options field.

 
by Dinesh Thakur Category: Multiple Access

NRZ-L (No return to zero level): this kind of encoding uses negative voltage to represent a binary 1 and positive voltage to represent a binary 0. As shown under: non return to zero is related with the voltage i.e. voltage never returns to a value of zero and the value of the voltage during a bit time is known as level. bit time is related with the amount of time one bit of data occupies.

 
by Dinesh Thakur Category: Multiple Access

SDH recommendation was standardized by ITU-T (G.707 and G.708):

• G.707: Synchronous Digital Bit Rate;

• G.708: Network Node Interface for the Synchronous Digital Hierarchy.

Found in SDH flows at 155, 622 and 2488 Mbit/s SONET.

 
by Dinesh Thakur Category: Multiple Access

CRC (cyclical redundancy checking) is a rather sophisticated error checking routine used to assure that two communicating computers are really getting the correct data. There are a whole bunch of these error correction and checking methods out there, but they all have pretty much the same objective: making sure that no data is lost or misinterpreted when two computers are exchanging information over the phone lines (through a modem, of course).



 
by Dinesh Thakur Category: Multiple Access

SONET/SDH standard was carry telephone speech, and it took many adaptations for the transport of frames and type of IP packets, ATM, or others. The successor of SONET/SDH has been launched in early 2002 and standardized by ITU-T as the OTN (Optical Transport Network). Its role is to channel packages on routes to 2,5, 10 and 40 Gbit/s. The corresponding recommendation G.709 carries the number.

 
by Dinesh Thakur Category: Multiple Access

MIMO technology (Multiple Input Multiple Output) is not new, but it hits the market that at the end of the first decade of the 2000s due to a very complex implementation. MIMO aims to carry multiple streams in parallel on different antennas but using the same frequency.

 
by Dinesh Thakur Category: Multiple Access

To achieve simultaneous multiplexing multiple telephone lyrics on the same circuit, Americans have adopted a standard for multiplexing 24 channels of 64 kbit/s on a support at 1544 Kbit / s. This channel is called DS-1. Europeans have responded to this technique by the E-1 channel multiplexing 30 voice channels on a support 2048 Mbit/s. From this basic multiplexing, a hierarchy has been defined, it is a multiple of the base channel, as in the case of Europe, or a little more complex, as in the US case, because an area of supervision rate-dependent.

 

Page 2 of 2



About Dinesh Thakur

Dinesh ThakurDinesh Thakur holds an B.SC (Computer Science), MCSE, MCDBA, CCNA, CCNP, A+, SCJP certifications. Dinesh authors the hugely popular blog. Where he writes how-to guides around Computer fundamental , computer software, Computer programming, and web apps. For any type of query or something that you think is missing, please feel free to Contact us.