ISDN in Japan
Who provides ISDN services in Japan?
NTT is the main provider, also Japan Telecom and DDI.
When did NTT introduce its ISDN services?
NTT introduced its ISDN services in April 1988.
What ISDN services do NTT offer?
NTT offers two ISDN services: INS-Net 64 and INS-Net 1500. (For the remainder of this FAQ, these services are referred to as INS64 and INS1500.)
What is INS64?
INS64 is an ISDN Basic Rate Interface (BRI). It consists of two B channels (Bearer channels) for voice, data, and fax transmission and one D channel (Delta or Data channel), which is used to control the B channels. The D channel can also be used to transfer packet data. Each B channel can transfer data at up to 64 kbps. INS64 can be used with existing copper telephone cables, making conversion both simple and cheap. The two B channels can be multiplexed for a combined data rate of 128 kbps.
What is INS1500?
INS1500 is an ISDN Primary Rate Interface (PRI). It consists of 23 B channels (Bearer channels) for data transmission and one D channel (Delta or Data channel). Unlike INS64, INS1500 requires a fiber optic connection between NTT and customer premises. INS1500 can be boosted up to 24 B channels by using a separate INS64 line for the D channel. The 23 B channels can be multiplexed together for a maximum data rate of 1.5 Mbps.
Do I need INS64 or INS1500?
INS64 is designed for home and small office applications. INS1500 is designed for large organizations that use a PBX (Private Branch Exchange) system.
How many ISDN customers does NTT have?
In mid-1992, NTT had about 156,000 customers using INS64, and about 550 using INS1500. Driven by the desire for faster Internet access, and the falling prices of ISDN hardware, NTT achieved 2.6 million customers in 1997.
The following graph shows the number of contracts completed since INS64 was introduced in 1988.
19881,198
198919901991199219931994199519961997
(Figures taken from the Asahi Shimbun Japan Almanac 1997 and Daily Yomiuri)
In the third quarter of 1996, applications for ISDN lines exceeded those for analog lines for the first time: 139,000 ISDN contracts compared to 96,000 analog line contracts.
Is ISDN available throughout Japan?
According to NTT, yes.
Do I need a new telephone line?
No. Your existing telephone line can be converted to ISDN (NTT perform tests to see whether your existing telephone cables can be used. Older lines may need replacing).
Will I have to change my telephone number?
As of April 1997, 96% of NTT lines can be converted to ISDN without a number change. NTT say this will be 100% by December 1997.
Is ISDN expensive?
Surprisingly, no. NTT's ISDN offerings compare favorably with those of other telephone companies. In fact, for comparable services, NTT's monthly charges are less than those in the UK, Germany, France, Belgium, and about the same as those of the United States. By using existing twisted-pair copper cables, installation can cost as little as ¥2,800.
What is INS64 Lite?
For just ¥640 extra in monthly fees, INS64 Lite provides you with an ISDN telephone line and eliminates the hefty ¥72,000 subscription right fee that you'd have to pay for a new telephone line, an ideal service for those who don't own a subscription right.
If you use INS64 Lite for up to nine years and four months, NTT claim it works out cheaper than buying a subscription right. Subscription rights, however, can be sold for about ¥50,000. So in effect you may have to pay just ¥22,000, making the INS64 Lite break point just under three years. See INS64 Lite charges.
What about usage charges?
Calls cost exactly the same as with regular telephone lines.
Is ISDN installation complicated?
No. Compared with ISDN services in other countries, NTT have greatly simplified the application procedure, installation, and eliminated a lot of the jargon. Don't be put off by ISDN installation horror stories from the United States. Thanks to NTT ISDN installation in Japan is easy.
What does a typical ISDN system look like?
Most people convert to ISDN for faster Internet access or the extra telephone line. A typical system looks something like the following. (TA/DSU with telephone and fax connected to individual analog ports and a computer connected to the DTE port.)
What if I already have two analog telephone lines?
You have two choices: Keep using both analog lines at ¥4,280/month (¥5,200/month for business customers), or change one line to ISDN, give the other line a service holiday, and pay just ¥3,730/month to have two telephone numbers on the same ISDN line (¥4,530/month for business customers). This includes ¥900/month for an additional telephone number.
What is a service holiday?
NTT offers two types of service holiday: temporary disconnection or suspension. With the former, you get to keep the telephone number, and can remain disconnected for as long as you want. However, there is a monthly charge. With the latter, you lose your telephone number, and there's a five year limit to how long you can suspend the service. However, no monthly charge is required. An NTT sales person told me that service holidays are free and indefinite, and that NTT sends a reminder after 10 years? I advise you to check it out for yourself before deciding.
Could I sell one of my lines?
Yes. You can sell your subscription right or transfer it to a friend or relative. NTT does not do this, but there are many companies offering this service.
How soon can I get ISDN?
Depending on your area, NTT may fix a date for installation within two weeks of your application.
How long does installation take?
Obviously this depends on your telephone setup, but a basic line conversion may take only 10 minutes--mine did!
Is ISDN an International Standard?
Yes. The CCITT (International Telegraph and Telephone Consultative Committee) is one of several committees operating under the auspices of the ITU (International Telecommunications Union), which has been associated with the U.N. (United Nations) since 1948. CCITT discussions of an integrated services network first took place in 1968. As the driving force behind ISDN, the international ISDN standard in use today is the result of CCITT recommendations.
Who provides international ISDN services?
KDD, IDC, and ITJ. See Resources.
How else is ISDN being used in Japan?
| Karaoke: If you've been to a tsushin karaoke bar or box, you've already experienced one of the more fun applications of ISDN--karaoke on demand. Instead of using clumsy and expensive laser discs, tsushin karaoke centers use ISDN lines to download MIDI song data and lyrics in real time from massive servers with vast libraries of karaoke songs. A typical karaoke server may contain over 10,000 songs. In this picture you can see the ISDN TA just below the TV. The bottom two units contain video CDs for background images. For some songs, however, MPEG video is delivered in real time via the ISDN feed. |  |
POS (Point of Sale): Supermarkets and convenience stores are using ISDN to transmit sales data to central offices. One of NTT's first POS clients was Seven-Eleven, with its nationwide chain of more than 4,500 convenience stores.
| ISDN Payphones: ISDN payphones are commonplace in Japan and can be found in call boxes, public spaces, and even telephone boxes for the disabled. They usually have jacks for analog modems and digital ISDN equipment, allowing the mobile computer user to check e-mail and send files. A large display provides instructions in both English and Japanese.  |
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| PHS (Portable Handy phone System): PHS telephone signals are picked up by small antenna, often mounted atop NTT telephone boxes, like the one shown here. From here the PHS telephone signal is carried via ISDN to the nearest NTT exchange. |  |
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Created: 16 May 1997. Modified: 13 September 1998.
Copyright (c) 1998 Paul Findon. All rights reserved.