Whether the call is made from a private home or a business environment, the caller’s carrier knows that when the prefixes 0800, 0808, 0844, 0845, 0870, and 0871 are dialled, the call is an NGN and the caller is then charged according to the appropriate rate band.

Let us use 0845 365 0500 as an example.

When 0845 is dialled, this means the caller is charged the cost of a “local rate” call at about 3.36p per minute + VAT.

The next three digits 365 direct the call within the Public Switch Telephone Network (PSTN) to Greystone’s carrier switch. The call is delivered there. It is delivered no further by the caller’s carrier.

Greystone’s carrier switch has the responsibility to deliver the call to Greystone’s underlying geographic STD number.

The last four digits dialled by the caller (0500), dictate to which STD number the call should be routed; in this case to 01606 814 868. The routing can be changed at any time to other STD numbers if required.

The call is delivered seamlessly - the caller experiences no loss of quality.

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