IP telephony in Japan
In Japan, IP telephony is regarded as a service applied by VoIP technology to the whole or a part of the telephone line. As of 2003, IP telephony services have been assigned telephone numbers. IP telephony services also often include videophone/video conferencing services. According to the Telecommunication Business Law, the service category for IP telephony also implies the service provided via Internet, which is not assigned any telephone number.
IP telephony is basically regulated by Ministry of Internal Affairs and Communications (MIC) as a telecommunication service. The operators have to disclose necessary information on its quality, etc., prior to making contracts with customers, and have an obligation to respond to their complaints cordially.
Many Japanese Internet service providers (ISP) are including IP telephony services. An ISP who also provides IP telephony service is known as a “ITSP (Internet Telephony Service Provider)”. Recently, the competition among ITSPs has been activated, by option or set sales, in connection with ADSL or FTTH services.
The tariff system normally applied to Japanese IP telephony is described below;
• A call between IP telephony subscribers, limited to the same group, is usually free of charge.
• A call from IP telephony subscribers to a fixed line or PHS is usually a uniformly fixed rate all over the country.
Between ITSPs, the interconnection is mostly maintained at VoIP level.
• Where the IP telephony is assigned normal telephone number (0AB-J), the condition for its interconnection is considered same as normal telephony.
• Where the IP telephony is assigned specific telephone number (050), the condition for its interconnection is described below;
o Interconnection is sometimes charged. (Sometimes, it is free of charge.) In case of free-of-charge, mostly, communication traffic is exchanged via a P2P connection with the same VoIP standard. Otherwise, certain conversions are needed at the point of the VoIP gateway which incurs operating costs.
Since September 2002, the MIC has assigned IP telephony telephone numbers on the condition that the service falls into certain required categories of quality.
High-quality IP telephony is assigned a telephone number, normally starting with the digits 050. When VoIP quality is so high that a customer has difficulty telling the difference between it and a normal telephone, and when the provider relates its number with a location and provides the connection with emergency call capabilities, the provider is allowed to assign a normal telephone number, which is a so-called “0AB-J” number.
The Ministry of Internal Affairs and Communications is a cabinet-level ministry in the government of Japan. The English name Ministry of Public Management, Home Affairs, Posts and Telecommunications (MPHPT) was used prior to 2004. It is housed in the 2nd Building of the Central Common Government Office at 2-1-2 Kasumigasaeki in Chiyoda, Tokyo, Japan.[1]
The purpose of this ministry is to oversee improvements to the Japanese administrative organization and civil servant system, manage local governments, elections, telecommunication, posts, governmental statistics and all concerning national basic system[clarification needed].
It was created on January 6, 2001 by the merger of the Ministry of Home Affairs the Ministry of Posts and Telecommunications and the Management and Coordination Agency
The Minister of Internal Affairs and Communications is appointed from among the members of the cabinet. Kazuhiro Haraguchi currently holds this post.
Asymmetric digital subscriber line (ADSL) is a form of DSL, a data communications technology that enables faster data transmission over copper telephone lines than a conventional voiceband modem can provide. It does this by utilizing frequencies that are not used by a voice telephone call.[1] A splitter – or microfilter – allows a single telephone connection to be used for both ADSL service and voice calls at the same time. ADSL can generally only be distributed over short distances from the central office, typically less than 4 kilometres (2 mi), but has been known to exceed 8 kilometres (5 mi) if the originally laid wire gauge allows for farther distribution.
At the telephone exchange the line generally terminates at a DSLAM where another frequency splitter separates the voice band signal for the conventional phone network. Data carried by the ADSL is typically routed over the telephone company’s data network and eventually reaches a conventional internet network.
Fiber to the x (FTTx) is a generic term for any broadband network architecture that uses optical fiber to replace all or part of the usual metal local loop used for last mile telecommunications. This generic term originates as the generalization of several configurations of fiber deployment (FTTN, FTTC, FTTB, FTTH…), all starting by FTT but differentiated by the last letter, which is substituted by an x in the generalization.

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