ISDN and Fax
Can I use my fax machine with an ISDN line?
Yes. Your G3 fax can be connected to an analog port on the TA.
What's a G3 fax machine?
Most fax machines in use today are of the G3 type, and transmit data at speeds of up to 9,600 kbps. Although scanning, encoding, and compression techniques are performed digitally, the actual transmission is still performed by what is essentially a built-in analog modem. In 1991, error correction, improved data compression, and the higher speed of 14.4 kbps were added to G3. Fax modems for use with personal computers often feature the higher speed of 14.4 kbps, but the speed automatically falls back to 9,600 kbps when the receiving device does not support the higher speed. Two fax resolutions are usually provided, the standard 200 x 100 dpi mode, and a 200 x 200 fine mode.
Can I still send faxes via my fax/modem?
Yes. Your fax/modem can be connected to another analog port on the TA.
How should I configure the TA port connected to my fax/modem?
Set it to modem, not fax.
Can I send faxes using just a TA?
No. Don't "hang up" your fax/modem for good just yet.
The communications software RVS-COM for Windows 95/98/NT, made by the German company RVS Datentechnik, allows, among other things, ISDN TAs and routers to be used to send and receive faxes. Several units sold in Japan are supported (see the compatibility list).
Does that mean I'll have to keep my fax/modem?
Yes. If you want to send faxes from your computer you'll need your fax/modem. Typical fax software requires a fax/modem and will not work with just a TA.
Does that mean if I don't yet have the ability to send faxes from my computer and plan to install ISDN I still have to buy a TA and a fax/modem?
With most TAs, yes. The Suntac TS128GA2M TA, however, has a 33.6 kbps fax/modem built-in, so you get the best of both worlds: ISDN for Internet access, and a fax/modem for sending faxes or connecting to online services that do not yet support ISDN.
Some US manufacturers are producing plug-in cards that feature both a TA and an analog fax/modem. The Courier I-modem, for example, features a TA and V.34 fax/modem, one analog port, and is available for Macs and PCs. As yet, it is not being sold in Japan.
Can a TA distinguish between voice and fax calls?
That depends on the sending equipment. If the caller is using an ISDN telephone or G4 fax, information about the type of call is transmitted via the ISDN D channel informing the receiving device whether it's voice or fax. If the source is an analog telephone, however, there is no way to convey information regarding the type of call until it is answered. Although it is possible, TA permitting, to pass a fax call from a telephone to a fax machine if you hear the beeping tones of a fax machine, optional Dial-In telephone numbers offer a more convenient solution.
How do I transfer a fax call from my telephone to my fax machine?
Obviously this depends on your TA. For the Aterm IT55, the procedure goes something like this:
First, fire up your Raku-Raku utility and turn on "tsushin chu tensou" on the "anarogu pooto kyoutsuu touroku" page. If you can't find this option, you need to upgrade your IT55 at the Aterm Web site.
1. The phone rings.
2. You pick up the handset and hear fax tones.
3. Yes, must be a fax! Let's transfer the call to Port A as that's where
the fax/modem lives.
4. Press the switch hook once. This will not terminate the call but put
Port B to a transfer mode.
5. You will hear special short beeps "asking" you for the target
port number.
6. Press [#] [*] [1] and hang up the handset.
7. The call will be transferred to Port A and away you go!
What are G4 fax machines?
G4 fax machines are designed for use with ISDN, offer faster transmission speeds, higher quality, and improved transmission reliability. Some G4 machines can be connected to your computer and used as a 400 dpi laser printer.
How much faster is G4?
G4 is six times faster than G3. It takes about six seconds to transmit an A4 page between G4 fax machines, compared to 37 seconds for G3 machines.
G337 seconds
G4
Does G4 makes use of the two B channels?
Yes. Using the two B channels, most G4 machines can send and receive at the same time, so a single G4 can do the work of two G3s. For example, if while transmitting a fax someone tries to send you a fax, the G4 machine continues transmitting and spools the incoming fax to a buffer (hard disk, memory). When the first transmission is complete, the received fax is printed.
How much better is the quality?
G3 fax machines support two image resolutions: 200 x 100 dpi (standard mode), and 200 x 200 (fine mode). G4 fax machines support a resolution of 400 x 400 dpi, which is as good as most laser printers. In addition, G4 features 64 levels of gray, so text is easier to read and illustration and photo fidelity is preserved.
Can G4 send to G3?
Yes, although the transmission speed is limited to that of the G3 fax (9,600 kbps or 14,400 kbps).
What about the fax quality?
When a G4 machine transmits to a G3 machine, the G4 machine switches to a G3-compatibility mode, so the fax quality is the same as that for G3. Using a G4 machine at the source, however, may provide better results.
Can G3 send to G4?
Yes, so long as the G4 machine is G3 compatible.
Is there a way to send at the G4 speed?
Yes. NTT have an optional service called G4 F-Net that allows you to burst G4 faxes to G3 machines at G4 speeds. Essentially F-Net acts as a buffer, allowing the G4 to disconnect when it's done its bit, and feeding the data through to the G3 at a more leisurely pace.
Does G4 F-Net cost more?
Yes. See G4 F-Net charges.
Is F-Net easy to use?
Yes. All you have to do is dial 161 before the fax number.
Are G4 fax machines readily available?
No. Don't rush out to your local denki ya just yet. The only G4 fax currently available are office-type machines, made by NTT and NEC.
How much is an office G4 fax machine?
About ¥100,000 for an office-type machine. A typical G3 fax machine for office use costs around ¥70,000.
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Created: 16 May 1997. Modified: 5 January 1999.
Copyright (c) 1999 Paul Findon. All rights reserved.