From: cstorry@gandalf.ca (Chuck Storry)
Subject: Re: Passive bus??? was: Re: isdn equipment
Organization: Gandalf Data Ltd.
Date: Thu, 1 Oct 1992 17:10:57 GMT

In <1acpoeINNg8g@agate.berkeley.edu> cliff@garnet.berkeley.edu (Cliff Frost) writes:

>In article <1992Sep27.032045.29386@xtcn.com>, lamb@xtcn.com (Richard Lamb) writes:
>|> Geez . I didnt realize how many people wanted the NT1 outside.

>I'm pretty surprised by this myself.  My reaction is who wants to pay an
>extra $100-200 for an external device or two (the NT NT1 is two large
>pieces wasting space on my floor).

The real cost may be closer to $500 today, hence there may be some cost
savings to integral U interface.

>In particular, I don't (yet) give a hoot about the passive bus.  I guess
>I can see why some Phone Phreaks might want the passive bus, it looks like
>a home LAN for your native ISDN telephones, but I can't see that as being
>a large part of the user base.  What really exciting things can I do with
>an ISDN phone that I can't do with beefed up POTS service and fancy phones?

I'm not a voice expert but I gather that all current voice features are 
available on ISDN (although some may be accessed in a proprietary manner)
in addition some new ones which may be interresting to certain users. The
one that comes to mind is the ability to get calling line id for an incoming
call while a call is in progress, instead of the call waiting beep, 
putting your current conversation on hold then talking to the incoming
call only to find out it was some call you didn't want anyways, you
just look at the calling line id while still talking and make that decision
or let your fancy phone do it for you.

>I want my LAN at home to be a real LAN (eg ethernet or localtalk, or even
>token ring), not some one-or-two-terminal-at-a-time thingamajig.  And I
>want my ISDN connection to be a portal from my home LAN to the Internet
>(which it is doing nicely now).

The uses I have for passive bus are not to interconnect devices on the
BRI together but in fact to allow multiple single devices simultaneous
attachment to the BRI. In case you weren't aware, your fax machine, phone,
data TA, answer machine, etc can not be "paralleled" together onto the
U interface. If you want all these things and want them on the same BRI
(of course only 2 B channels can be used at a time) then they must be all
built into the same physical device (granted some fax, phone answering equip
is available) it is by far the exception and can be expensive. The passive
bus solution lets you buy your kit from whoever you want and then plug it
all together, not necessarily to talk to each other but to share access to 
this "Integrated" service line. Also you can upgrade, add or change
functionality as your application justifies.

Another interresting consideration for those who still want a U interface
on their CPE; should this interface simply be a U termination or should it
really look like an NT1 and not only terminate the U interface but also
present the S interface to other devices for "parallel" attachment ?

Who builds this NT1 function in ? the phone, the data ta, the fax ...

>So, I must be missing some obvious Hot Things I could do with this
>passive bus besides warm my cats (the giant NT1 boxes are good at that ;-).
>Maybe someone can enlighten us?

>	Thanks,
>		Cliff Frost
>		UC Berkeley

>ps I guess the above note might seem snide.  It's not meant that way, I'm
>asking a serious question.
-- 
Chuck Storry, Principal Designer      CAnet: cstorry@gandalf.ca
Gandalf Data Ltd.                     Voice: (613) 723-6500
130 Colonnade Rd So, Nepean, Ontario  Fax: (613) 226-1717
Canada  K2E 7M4