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	Links I-NET Introduction Types of Connections Typical Applications Facilities Advantages Other Services Registration Tariff Telephone Connection Phone Plus Facility ISDN Intelligent Network Leased Circuits National Trunk Services Int. Trunk Services In Case of Difficulties or Suggestions to this site : Email: helpdesk.mumbai@mtnl.net.in

TYPES OF CONNECTIONS

Inet (Phase II) offers the following types of connections : X.25, X.32, X.28 leased, X.28 dialup and Frame Relay* ( * Frame Relay service will be provided initially in Group A and B cities only)

X.25 Connections

An X.25 customer with the help of a computer/terminal with CCITT X.25 compatible software and hardware can receive and originate several simultaneous calls. An X.25 link is similar to telephone junctions extended to PABX. X.25 connection is provided on leased line (2 wire or 4 wire) from the Inet exchange. The speed of connection can be 2400, 4800, 9600, 19200 or 64000bps. The modems used will be V.22 bis, V.29, V.32 bis, Data-Over-Voice, V.35 or 64 Kbps line drivers..

X.32 Connections

X.32 access enables X.25 customers to have a backup access to Inet using PSTN. It provides all the functionalities of X.25 but on dialup mode. The speed of connection can be 2400, 4800 or 9600 bps. Modems used will be V.32 bis.

X.28 Leased Connections

An X.28 lease customer can receive or originate only one call at a time. This is similar to a normal telephone connection. This customer can use computer/terminal with appropriate communication software (like Procomm, Xtalk etc.). The speed of connection can be 1200, 2400, 4800 or 9600 bps. This connection is also provided on leased line from the Inet exchange to the customer's premises. The modems used will be V22 bis, V32 bis or Data-Over-Voice.

X.28 Dialup Connections

An X.28 Dialup customer can use any computer/terminal with appropriate communication software (like Procomm, Xtalk etc.) to originate or receive calls at 300, 1200, 2400, 4800 or 9600 bps using a TEC approves, PSTN dialup modem connected to his telephone. In a two step dialing procedure the customer first dials a local telephone number of the Inet exchange to get connected to Inet after which he can establish call to any other customer of Inet or overseas data networks. This does not require a leased line from the Inet exchange to the customer's premises. The modems used will be V.21, V.22 bis or V.32 bis.

Frame Relay Service

Frame Relay service is available only from Group A and Group B cities. Frame Relay customers can have PVCs (Permanent Virtual Circuits). It can be used for providing high speed connectivity between LANs in different cities.
Frame relay is a modified form of packet switching service. It provides error free data circuits with capability of band-width on demand.

INTERFACES

The modem interfaces supported in general are V.24, V.28, V.35 or G.703 (co-directional).

STANDARDS

Inet supports CCITT standard protocols X.3, X.25, X.28, X.29, X.32 and X.75.