The standard connector for unshielded twisted pair cabling is a RJ-45 connector. This is a plastic connector that looks like a large telephone-style connector.

The most common type of connector used with coaxial cables is the Bayone-Neill-Concelman (BNC) connector. Different types of adapters are available for BNC connectors, including a T-connector, barrel connector and terminator. Connectors on the cable are the weakest points in any network.

It is the shortest frame which consists of flag, address, control, FCS and it carries commands and responses.

Coaxial cabling has a single copper conductor at its centre. A plastic layer provides insulation between the centre conductor and a braided metal shield. The metal shield helps to block any outside interference, therefore we use it in CABLE TV. Thin coaxial cable is known as thinnet (10base2). The most common ones are RG 59(Coaxial cable) and a low loss cable is RG 6, both are 72 ohm for TV sets and antennas.

 FTP, SFTP and TFTP are used for transferring files from one system to another through internet and web server. FTP  is a standard network protocol used to copy a file from one host to another over a TCP -based network, such as the Internet. The SSH File Transfer Protocol is not related to FTP except that it also transfers files and has a similar command set for users. A similar protocol TFTP (Trivial File Transfer Protocol) provides connectionless file transfer over UDP.This is only suitable for very small files; for example, uploading configuration files to routers. 

The checksum field is the 16 bit one's complement sum of all 16 bit words in the header and text. If a segment contains an odd number of header and text octets to be checksummed, the last octet is padded on the right with zeros to form a 16 bit word for checksum purposes. The source port and destination port also have 16 bits.

Domain name system is hierarchical (cs.uktech.gov.in) (Uttrakhand technical University in India ) and distributed (systems are connected to the network). So, this convention should work every where.

It is strchr() not a strchar(). There is no such function called strchar().

This is the correct option. 

Router is used to connect two WANs. Router works in Network layer. So, WANs of different protocols are supported by router.

In Multi-access system in Global Mobile system, each user has different band pass filter to send or receive the data.

Base station and Mobile Switching Centers (MSC) are related to radio relays. The BSC may be coupled to a mobile switching center (MSC) and a packet data serving node (PDSN) between MSCs, circuit connections provide the handover mechanism which services calls as users roam from one service zone to another.

Physical data model provides the concepts about physical storage of data.

In relational model, both entity and relationships are represented as tables.

Conceptual level is responsible for tree structure and logical relationship that exists among data.

It performs translations of DDL statements into schema definition called meta data in the DBMS catalog.

Clustering index file consists of entries with two fields - the clustering field value and the block pointer to clustered block of records.

S-HTTP allows the client and servers to execute all encryption and decryption of transactions.

It is an open, vendor-neutral, non-proprietary, license free specification for securing on-line transactions.

UNIX provides far more security to host and remote host as compared to any OS available nowdays.

It is used to match the MACC (physical address) of a system to the logical (IP) address. This is used for a diskless computer.

SET protocol has developed a single method that consumers and merchants use to conduct bank card transactions in cyberspace as securely and easily as they do in retail stores today.

Bridges operate in both physical and datalink layers. So, the layer supports a data link layer (layer 2). Bridges work at the Data Link Layer of the OSI model because they work at this layer, all information contained in the higher levels of the OSI model is unavailable to them. Therefore, they do not distinguish between one protocol and another.

1 is an idle value of state of line in synchronous transmission.

Both 2^nd and 3^rd options are correct because sliding window is used for both flow control and protocols where reliable in-order delivery of packets is required, such as in the Data Link Layer (OSI model) as well as in the TCP.