A Terminal Adapter is an electronic device that interfaces a computer to an external digital communications line, such as an Integrated Services Digital Network (ISDN) phone line. A terminal adapter is a bit like a modem and often referred to as modem but because it is digital, a terminal adapter is not exactly a modem, A modem needs to convert between analog and digital signals, on the other hand, a terminal adapter only needs to pass along digital signals. As ISDN becomes more common, future computers might probably have terminal adapters built in. As of now you need to purchase a separate terminal adapter if you want ISDN access. You can get an internal adapter or an external adapter than connects to your computer’s serial port.

Packet-

A packet refers to the unit of data that is in passage between an origin and a destination on the Internet or any other packet-switched network. Every page that you receive on the Internet comes as a series of packets, and every e-mail you send leaves as a series of packets. Networks that ship data around in small packets are called packet switched networks. The TCP/IP protocol breaks large data files into smaller “packets” for swift transmission over the Internet. When the data reaches its destination, the protocol makes sure that all packets arrived without error. A typical packet contains perhaps 1,000 or 1,500 bytes. Packets are also referred to by other names like frame, block, cell or segment depending on the type of network.

Packet Switching-

Packet Switching refers to the method of moving data around the Internet that allows many people to use the same lines at the same time. In packet switching, all data being transferred from a source is divided into packets, with each packet bearing the address of its origin and destination. This enables packets from different sources to be simultaneously transferred, sorted and directed on the same line. Each packet is then transmitted individually and can even follow different routes to its destination. Once all the packets forming a message arrive at the destination they are reassembled into the original message. ,A packet-switching scheme is an efficient way to handle transmissions on a connectionless network such as the Internet

Synchronous Digital Hierarchy is a method used for multiplexing many circuits with a low bit rate onto fewer circuits with a higher bit rate, and vice-versa i.e de-multiplexing. Synchronous Digital Hierarchy is the international equivalent of Synchronous Optical Network. Both the technologies provide faster and less expensive network interconnection as compared to the traditional PDH (Plesiochronous Digital Hierarchy) equipment. Synchronous Digital Hierarchy is primarily used in the telecommunication industry to carry telephony traffic. This network can also be used to carry IP traffic. SDH can improve network reliability and performance, offers much greater flexibility and lower operating and maintenance costs, and provides for a faster provision of new services.

With relation to computer technology, “on the fly” describes activities that develop or occur dynamically rather than as the result of something that is statically predefined. For instance, the page content sent to the user from a Web site can be developed on it on the basis of dynamic factors such as hours of a day, the time and date can be seen.The Web server mainly calls an application program to produce the “on-the-fly” page that is to be given back. But there are several techniques for on-the-fly page development which include the use of cookies, the server side which include Microsoft’s Active Server Pages, and PHP. A page created on the fly may have its own URL but this is not necessary which contains all data on which the page depends upon.

It is an open architectural network helping in the building of distributing systems in which scale, rate of change and complexity of interactions in networks which are necessary and which can’t be addressed by the present technologies.

This provides a very flexible infrastructure for the services to be delivered and for immediate communications between clients who are aware of these services. It also enables developers to create network-oriented services regardless of hardware/software.

Lightweight Directory Access Protocol is a network protocol for information and modification of directory services that run over TCP/IP. The directory services refer to set of information with attributes of the same origin that are highly organised in alphabetical or hierarchical order.

One of the examples is the Telephone directory in which a series of names organised alphabetically, with an address and phone number attached.