Subscriber Trunk Dialling (STD) enables you to directly dial a phone no. in another City / Station and engage in Telecommunication.

Each distant City / Stn. is allotted a STD dialing prefix code. While dialing using STD you will have to dial continuously the STD prefix [ “0” for National STD, “00” for International destinations “000” for Home Country Direct ] followed by the STD Stn. code (e.g. 11 for Delhi) and then the distant Stn. / City phone no.

HOW STD CALLS ARE CHARGED?

Billing of STD Calls is determined based on the following criterion :

a) Distance of the Distant City / Stn. from the Calling Stn.

b) Type of the day ( holiday or normal ).

c) Time when the Call is answered by the distant party.

d) The Service accessed ( e.g. National or International ).

Invariably, one call unit is incremented on answering by the distant called party followed by one or more call meter units increments at regular intervals till the connection lasts.

However, You will not be charged if you replace the receiver before dialing all the
digits required to be dialed or if the wanted number is busy or there is no-answer.

For the purpose of charging National STD Calls, the country is divided into a no. of Long Distance Charging Areas (LDCA). Each LDCA comprises of several Short
Distance Charging Areas (SDCA). For each LDCA, there is one Stn designated
as Long Distance Charging Centre (LDCC). For each SDCA also, there is one
Stn designated as Short Distance Charging Centre (SDCC).

Calls between two stations in two different non-adjacent LDCAs are charged
depending on the radial distance between the corresponding LDCCs.

Calls between two stations in two different SDCAs located in same LDCA or
adjacent LDCAs are charged depending on the radial distance between the
corresponding SDCCs.