Toll restriction or toll denial is a
telephony
Telephony ( ) is the field of technology involving the development, application, and deployment of telecommunications services for the purpose of electronic transmission of voice, fax, or data, between distant parties. The history of telephony is ...
feature offered by a telephone company that configures a
telephone line
A telephone line or telephone circuit (or just line or circuit industrywide) is a single-user circuit on a telephone communication system. It is designed to reproduce speech of a quality that is understandable. It is the physical wire or oth ...
to be configured so that it is impossible to originate
long-distance calls from that line, or to accept charges reversed to the
telephone number
A telephone number is the address of a Telecommunications, telecommunication endpoint, such as a telephone, in a telephone network, such as the public switched telephone network (PSTN). A telephone number typically consists of a Number, sequ ...
by other parties. Such lines usually allow calls to be made to no-charge numbers locally and toll-free so that customers can still initialte local and some long-distance calls.
Most commonly this restriction is applied at the request of the owner of the premises, who does not wish to be subject to unlimited liability for costly unauthorised calls made by others at the site. Restriction of calls to overseas or
premium-rate telephone number
Premium-rate telephone numbers are telephone numbers that charge callers higher price rates for select services, including information and entertainment. A portion of the call fees is paid to the service provider, allowing premium calls to be an ...
s are common options on some systems, such as
voice over IP
Voice over Internet Protocol (VoIP), also known as IP telephony, is a set of technologies used primarily for voice communication sessions over Internet Protocol (IP) networks, such as the Internet. VoIP enables voice calls to be transmitted as ...
.
Private branch exchange
A business telephone system is a telephone system typically used in business environments, encompassing the range of technology from the key telephone system (KTS) to the private branch exchange (PBX).
A business telephone system differs from ...
clients are often able to configure toll restriction on a per-extension basis through the local PBX, either blocking all trunk calls or requiring that a numeric password be dialled to complete the call.
Toll restriction features are categorized in a set of seven classes, Class 0 through Class 6.
Telephone companies may sometimes require high-risk-account customers, or those requiring basic phone service for security and health reasons, to accept toll restriction.
Telephone service enhanced features
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