response 126 of 203:

Aug 13 06:17 UTC 1997

  re:  putting money in an interest-earning account -- how would that
  affect Grex's non-profit status and would the relatively miniscule
  amount of interest earned be worth the staff time used filling out
  whatever tax paperwork was needed?

response 128 of 203:

Aug 13 19:12 UTC 1997

I saw an ad for a PCMCIA ISDN modem for around $400. On the general principal
that PCMCIA equipment tends to be more expensive than its desktop equivalent,
it should be possible to get the ISDN routers for much less than $650 apiece.
You might want to shop around.

response 130 of 203:

Aug 13 21:20 UTC 1997

An ISDN "modem" is not the same as an ISDN router.

response 132 of 203:

Aug 13 22:39 UTC 1997

A real "ISDN modem" is pretty rare.  It's a thing that will talk to
ordinary voice modems at the other end (via ISDN to the CO, then via an
ordinary analog voice line to the other end.)  The major win is that it
gets rid of one analog hop.  It's something an ISP might do, if ISDN
lines were cheaper than ordinary phone lines (they aren't) and if the
modems were cheaper (they aren't).  You can also use ISDN for ordinary
voice conversations, and there are a few special features you can get
that way that you can't get with an analog line.

Electrically, ISDN looks like this:

central office
        talks via U loop over 2-4 wires to
NT1
        talks via T bus over 4-8 wires to
NT2
        talks via S bus over 4-8 wires to
1 to 8 devices

In europe (and elsewhere) the phone company owns the NT1.  In the US
(only) the subscriber provides the NT1.  The T bus only supports 1
device, but the S bus supports up to 8 devices.  The S & T busses are
otherwise similar; you only need an NT2 if you have more than one device
to hook up to the line.  In the US, because the NT1 is something the
subscriber has to provide, it is common to find equipment that has this
built in.

ISDN comes in to flavors, BRI and PRI.  PRI provides 23 B channels plus
1 D channel (or 30+1 over E1, found in europe..).  BRI provides 2 B
channels plus 1 D channel.  A B channel is a 64K channel, or one "voice"
connection.  A D channel is a 16K channel, used for control purposes.
One common use for a PRI is for a PBX, or a private phone switch (such
as you might find in a small office).  PRI's are also commonly used by
ISP's.  BRI's are what you might find in a home.  There are several
different standards for the control signals sent over the D channel;
hence some equipment that works fine in europe would be difficult to get
working here in the US (and visa-versa).

Because a BRI provides 2 B channels, for data purposes, it's common to
use both at the same time to talk to the same remote site.  Various
incompatible protocols are available to do this, one is called
"bonding".

One ISDN data channel merely provides a 64K synchronous full-duplex bit
circuit.  It does not provide for packet handshaking, compression, or
anything else.  For internet access, it is common to run "PPP" over
ISDN.  Some older ISDN internet devices did not provide for packet
compression, but newer ISDN devices commonly do so.

There are indeed a lot of ISDN devices available for the PC compatible
world.  These devices commonly interface to the ISA, EISA, PCI, or
PCMCIA busses.  Of course, these devices need software, in order to
function.  Unfortunately, all of the vendors we've located for such
peripherals have fallen prey to market pressures, and *only* provide
software for Windows, Windows NT, Novell Netware and similar proprietary
environments.  The problem with these environments is that they (a) cost
more, and (b) are less flexible, and (c) are not necessarily robust
enough to operate reliably (7/24) in a relatively hostile environment
(potentially hostile users, saturated network connection, unattended
operation.) The software for most of these cards is of course assuming
"personal" use, which means they're going to contain features like
part-time use, and colorful glossy brochures, but aren't necessarily
going to contain features like reliable automatic error recovery (a
pop-up window may be "good enough"), or subnet routing (for machines
connected via ethernet to the PC).

Another sort of ISDN device that is not hard to find is something that
connects an ethernet to an ISDN line.  The Ascend pipeline is one such
product.  These aren't particular flexible either, but they have
acquired a reputation for reliable unattended operation, and are
relatively simple devices unlikely to malfunction.  For our purposes, we
want a device that includes the NT1 interface integrated, supports some
form of bonding and compression, and will support these features when
talking to whatever is at the other end.  Right now, that would be a
clone of the same device, but in the future, it's desirable to pick
something that would be likely to work with an ISP too.  Some older
pipelines would only route to a few devices on the local ethernet, and
not further, needless to say, that would not do at all for the
"internet" end of grex's internet connection.  That would also not do if
we find in the future that we need to implement a firewall, or have more
than a few devices on the local ethernet.

There are lots of other ISDN devices out there.  For instance, there are
ISDN devices that connect to an ordinary serial port (data rates may be
limited to the speed of the serial port), there are computers that talk
ISDN directly (some of the newer sun workstations come with an ISDN
interface), there are gobs of ISDN cards for all sorts of other busses
(including VME, like we have on the sun4 machines), and there are many
different routers that support ISDN (like what you'd find at an ISP).
Most of these devices are either a bunch more expensive, have limited
functionality, and/or would be a lot of work to get working on grex.

The next step up from ISDN is a T1 line.  T1 is slightly cheaper than
PRI, and offers slightly more data througput (it runs over the same
physical lines as PRI).  We located one vendor of T1 cards for the ISA
bus, that we (or I at least) really liked.  They provided a freebsd
driver for their card, which would make it almost a no brainer for us to
get this going.  It would be a really great deal *if* we could find
somebody willing to give grex T1 internet connectivity (if we provided
all the hardware), and we had about $3K startup + $250/mo monthly to
throw into the physical connection.

response 134 of 203:

Aug 13 22:49 UTC 1997

Many ISPs are now using digital modems talking over PRIs or channelized T1
lines (kind of like a PRI, but without the signaling needed for ISDN data
connections) to talk to customers' analog modems, so that's pretty much the
ISDN modem concept Marcus was talking about in his first paragraph.  That's
the only configuration the new "56K" modems will function in.  One end of that
connection has to be digital.

response 136 of 203:

Aug 14 04:46 UTC 1997

  I think a T1 connection would be a substantial overreach for Grex..
  I don't think we have the hardware to support the users who would be
  needed to support such a thing on an ongoing basis.  The most common
  cause of death for systems such as Grex is over-expansion, not under-
  devlopment..

response 138 of 203:

Aug 14 17:42 UTC 1997

  I won't argue against the claim that Grex will eventually need
  (and be able to support) a T1, I'm just cautioning against the
  "if you build it, they will come" school of system expansion.
  Taking on large expenses in anticipation of a large influx of
  users that never wind up coming has killed many a small public-
  access system.

response 140 of 203:

Aug 19 12:53 UTC 1997

janc: are you speaking in third person in case he doesn't figure out the
connection?

response 144 of 203:

Aug 24 16:47 UTC 1997

  I have a call into Ameritech on this, but I belive that both ends
have been installed.   The Ameritech person who did the Pumpkin end
of the install was told the wrong building, but had my pager number
and called for help.  That got straightened out quickly, thanks to
our wonderful Ameritech contact Ken Kiernan's putting my pager number
on all service work. ;-)

response 146 of 203:

Aug 25 01:28 UTC 1997

   I have an order in, but it won't be shipped out 'till Monday--actually
I was too late for shipment then, but it also let me look and make sure
that no one else ordered them.  I see no evidence that anyone has.

response 148 of 203:

Aug 25 04:42 UTC 1997

How are we doing on collected pledges so far?