There are two sections here, one describing ISDN in general, and a table of various kinds of TA information. Some kind of disclaimer about as-isness and no guarantee of suitability and all that legal babble should go here, but I was too busy to talk with the lawyers.

Basic ISDN service involves a single pair (two wires) using digital coding to carry two data channels and one control channel. The data channels are called B channels, and each B channel can carry one voice call or one digital data signal. (The control channel is only used for dialing and some support functions, and is basically unimportant here.)

For most residential users, ISDN doesn't make that much sense. There are a couple of cases when it can be better than regular phone service, however. If you have two phone lines in your home, then one ISDN line can do the same work for less money. The equipment needed to use the ISDN line is actually less expensive than the street value of the 'used' telephone line permission fee that you paid to NTT for each line, so selling off one of the lines may actually generate a profit, as long as there are not special construction fees required.

While ISDN does give you the capability of two phone lines, it can be a little hard to use both of them effectively because the equipment at each end will tend to switch things around a bit looking for a free channel. If you want to use one line only for faxes, you can pay extra for the second phone line, but you can't be sure that the fax calls will arrive correctly, because if one of your B channels is in use, the equipment will tend to use the other B channel. In practice, this sort of thing usually doesn't cause too much problem, and if you have a new computer with the capability to automatically switch to fax mode as required, then you can just send and receive voice calls and faxes on the single number, or connect to the Internet, while still being able to call out (but only two things at a time).

If you can actually get one of the apparently hypothetical ISDN phones or true ISDN fax equipment, you can get a lot more capabilities, but mostly that equipment doesn't seem to be around. For example, you can assign (and pay for) a bunch of phone numbers, and your ISDN phone can tell you which one is being called. This might be useful if you wanted to run several businesses with separate phone numbers, kind of like a small PBX. The ISDN faxes can send very quickly, but only to another ISDN fax. So all in all, it seems like the main users of ISDN are just computerists who want more bandwidth to the Internet.

This table is just a general description of some of the TAs I've run across over the last year or so. A very idiosyncratic selection and description, to be sure, and I've tried to be generous about skipping what I can't recollect. And most of it should be checked with the manufacturers, too. These links go directly to the relevant TAs: MN128, IT55, IT45, IT35, ComStarz, TA/2A, Brain, PCM-CIA Cards, INS Mate 1, INS Mate V-5, Suntac....

Copyright 1997 by Shannon Jacobs. Must be a work of fiction?
I think that means you're allowed to freely use the ideas here, but not my precise expression of these ideas. And if you want to SELL them, then I definitely want a cut!

Feel free to send me your comments or suggestions, and if I work them in, I'll include colored acknowledgements, too. [But so far, no one has sent me anything. :-( ]

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Copyright ©1996-2000 by Shannon Jacobs	My weird disclaimer
Updated: 6/16/2000	Visitor:
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