ISDN and Telephones
Can I use my existing telephone with an ISDN line?
Yes. Your existing telephone can be connected to an analog port on the TA.
Can I use a dial pulse (DP) type telephone?
That depends on your TA. For example, only push-button (PB) telephones can be used with the NEC Aterm IT55DSU. The OKI PCLINK TA322DSU, however, supports both PB and DP type telephones.
Can telephones connected to the TA be used internally?
You mean like an intercom? Yes, although it depends on your particular TA. Both the OKI PC Link TA212 and NEC Aterm IT55DSU support this feature.
Will I be able to use my telephone in the event of a power failure?
Unlike analog telephone lines, which continue working in the event of a power failure, ISDN lines require power from the customer site. So if the power fails, your telephone lines fail as well. Of course, if your telephone requires a power source, usually in the form of a plug-in adaptor, to drive its convenience features, it wouldn't work in the event of power failure, anyway. The same applies to most cordless phones and fax machines. (The telephone on some fax machine may still work even with the power turned off.)
Some TAs, such as the NEC Aterm IT55DSU, have a battery backup feature, whereby the ISDN line can still be used in the event of a power failure. To use this feature you'll need a plain, unpowered push-button telephone.
If I connect both my fax machine and telephone to the TA, will they both ring when a call comes in, and is it possible for the TA to detect the type of call and route it to the appropriate device?
If the caller is also using INS64, your TA should be able to tell whether the incoming call is voice or fax and route it through to the appropriate device. This information is transmitted on the D channel before communications are established on a B channel. Of course, this may depend on the capabilities of your particular TA. If the call originates from a regular telephone, i.e., from a non-INS64 subscriber, it is not possible to detect the type of call and both devices will ring.
With the NEC Aterm IT55DSU it is possible to switch off call type detection and ringing for ports individually.
So what happens if I pick up the telephone and hear beeping fax tones?
With the NEC Aterm IT55DSU you simply transfer the call to your fax machine.
What about additional telephone numbers?
The call type detection problem can be remedied using additional telephone numbers, and that's what NTT's Dial-In service is all about. Dial-In provides additional numbers for each device, so fax and telephone can be called independently.
In the illustration below, the caller dials 474-XX01, which is the subscription right number. At the destination site, the telephones and fax machine all ring at the same time.
In the next illustration, the subscription right number has been assigned to the main telephone and Dial-In numbers assigned to the other telephone and fax machine. This time the caller dials 474-XX02 and only the other telephone rings.
How much does Dial-In cost?
Dial-In costs ¥1,000 to install and ¥900/month for each number.
How many additional numbers can I have?
Up to 100 per INS64 line.
What if I want all devices to ring when the subscription right number is called?
For this situation NTT offer the Global service. With Global, all devices ring when the caller dials the subscription right number, as shown below,
but when a Dial-In number is called only the device assigned that number rings, as shown below.
Your TA should allow you to select which analog ports work with Global. For example, you may want to enable it for telephones only, as shown in the following example.
You have to apply to NTT to use the Global service, and there's an option on the INS64 application form. Global is available only if you purchase additional Dial-In numbers.
What is an ISDN telephone?
An ISDN telephone is an all-digital telephone designed to take full advantage of the many features of ISDN.
Are ISDN telephones readily available?
No. Don't rush out to your local denki ya just yet. The only ISDN telephones I've seen are designed for office applications. Many telephones are being advertised as "digital", but this does not mean they are ISDN telephones.
Who makes ISDN telephones?
NTT and NEC are two ISDN telephone manufacturers that I know of.
How much is an ISDN telephone likely to cost?
Currently, around ¥30,000 for an NTT model.
What are the advantages of an ISDN telephone?
Having never seen one I'm not exactly sure. I suppose with an ISDN telephone digital-to-analog conversion takes place in the telephone itself, not the TA. Also there's a display for Caller ID and real-time billing. And if the caller is using an ISDN telephone, sub-addresses can be used to call specific ISDN devices at the destination site, eliminating the need for additional telephone numbers. ISDN telephones are probably more useful in office PBX applications.
What's sub-addressing?
By entering a sub-address number after the main telephone number callers can direct calls to specific devices on the INS64 line. Up to 19 sub-addresses can be used per line.
Can anyone use sub-addresses?
No. The caller must be using an ISDN telephone. Analog telephones connected to a TA, however, can be called using sub-addresses, because the TA handles the settings.
Is it possible to check call charges without an ISDN telephone?
Possibly. The Raku-Raku utility bundled with the NEC Aterm IT55DSU can display call charges for each port.
What is Tele-Hodai?
With NTT's optional Tele-Hodai service you pay a fixed monthly rate for all calls made to two specified numbers between 11 pm and 8 am, regardless of the number of calls or the duration of each call. Tele-Hodai is available for analog and ISDN lines. The former being called simply Tele-Hodai. The latter, INS Tele-Hodai. See Tele-Hodai charges.
What is Tele-Choice?
With NTT's optional Tele-Choice service you pay a fixed monthly charge and receive a fixed discount on all calls made to specified code areas. Two Tele-Choice plans are available: Plan 1, Plan 2. Under Plan 1 you pay 200/month for a 10% discount on all calls to four specified code areas. Under Plan 2 you pay ¥400/month for 15% discount on all calls to 10 specified code areas. Plan 1 is economical if your spend more than ¥2,000/month on calls to four code areas. Plan 2 is economical if your spend more than ¥2,670/month on calls to 10 code areas. With both plans you pay the fixed rate regardless of calls made. Tele-Hodai applies only to code areas outside of your area (i.e., not local calls). See Tele-Choice charges.
What is Voice Warp?
The optional Voice-Warp service allows you to redirect calls to another telephone. Calls can be redirected to analog telephones, ISDN telephones, or cellular telephones, but not to PHS phones. Calls originating from analog telephones, ISDN telephones, and public telephones can be redirected to another destination. Calls from portable and PHS phones cannot. The analog equivalent of INS Voice-Warp is Call Forwarding. See Voice-Warp charges.
What is Flexphone?
The Flexphone package consists of four optional services: Call Deflection, Call Transfer, Call Waiting, and Three-party Service. These services can also be purchased individually. All Flexphone services can be used with an ISDN telephone. The services you can use with an analog telephone depends on the capabilities of your TA. In order to control and set up Flexphone services the caller must have an ISDN line. See Flexphone charges.
Call Deflection redirects incoming calls to a specified telephone.
Call Transfer allows you to transfer a call in progress to another telephone.
Call Waiting allows you to put a call on temporary hold and answer an incoming call.
Three-party Service allows you to hold a three-way telephone conversation.
The Three-party service has two modes of operation: Mixing and Switching. In Mixing mode, all three callers can talk simultaneously. In Switching mode, only two callers can talk simultaneously. For example, A can talk to either B or C, but B cannot talk to C and vice versa.
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Created: 16 May 1997. Modified: 13 September 1998.
Copyright (c) 1998 Paul Findon. All rights reserved.