telecom@ucbvax.ARPA (10/15/84)
From: Jon Solomon (the Moderator) <Telecom-Request@MIT-MC>
TELECOM Digest Monday, 15 Oct 1984 Volume 4 : Issue 101
Today's Topics:
Carterfone
NSA breaking DES
Re: FAST Modems
Let's not blame the breakup for everything
Florida Wideband Fiber Optics Network
NOTES ON THE NETWORK
AT&T ISN
AT&T ISN
Recognizing Digital Signals
Two modems on one phone line
----------------------------------------------------------------------
Date: Thu, 11 Oct 84 21:38:45 EDT
From: Ron Natalie <ron@BRL-TGR.ARPA>
Subject: Carterfone
Actually, the act behind the Carterfone decision was even a more
facist act by the phone company. The Carterfone was a device that
could be equated to the modem Acoustic coupler and was used to patch
the phone into a radio. There was no electrical connection involved.
-Ron
------------------------------
Date: 11 Oct 1984 19:39 PDT (Thu)
Sender: TLI@USC-ECLB
From: Tony Li <Tli@Usc-Eclb>
Reply-to: Tli@Usc-Eclb
Subject: NSA breaking DES
In a paper by Diffie and Hellman, they describe a method for
exhaustive search which would enable someone to break the DES using a
large parallel architecture. This, however, is not the same thing as
the NSA breaking the DES. The NSA in it's infinite wisdom, helped
design the DES. The possibility exists that there is a trivial method
of attacking the DES, and that the NSA may have it. It may not take
more than a Vax....
Cheers, Tony ;-)
------------------------------
Date: 11 Oct 84 20:11:04 PDT (Thursday)
From: Kluger.PA@XEROX.ARPA
Subject: Re: FAST Modems
In many cases, 9600 bps 4 wire leased line modems can be used over the
dialup network by using two phonelines at the same time. Two phone
calls are placed, two phone lines are required at each modem location.
"Dual dial backup" equipment is available from several vendors
including Paradyne and Codex.
Larry
------------------------------
Date: Friday, 12 Oct 1984 06:03:06-PDT
From: goldstein%donjon.DEC@decwrl.ARPA (Fred R. Goldstein)
Subject: Let's not blame the breakup for everything
Les Waters' reprint from the CBBS is full of so many inaccuracies that
it isn't worth even responding to specifics. Once again, somebody who
has an axe to grind and knows little about the telephone industry has
written a Phillipic that seems to blame divestiture for everything
from the Spanish Inquisition and the Thirty Years' War to the sinking
of the Andrea Doria. Come on, folks, let's be reasonable!
"Information Terminal Service" tariffs go back many years; the
Oklahoma case was based on an ancient state tariff that predated the
widespread use of time-sharing, not to mention micros. It's a state
regulated matter, which hasn't been affected by the divestiture at
all, and if you don't like it, you can let your state regulators know.
In Oregon, one sole Commissioner runs the show and sets all telephone
rates. Other states have larger commissions, but I doubt if many of
them would really want everyone who bought a $229 modem at Toys-r-Us
to pay $50/month for $9 residential service. If Telco thinks the CBBS
is a commercial venture for money (there are some out there, of
course) then they pay business rates. It worked that way before 1983
and it still does.
Other local charging plans have been batted around for decades. New
York City hasn't had flat-rate residential or business service for
many years, and the Bell System (AT&T) started a big "usage sensitive
pricing" push around 1974. Never mind that most of their costs are
usage insen- sitive, USP gives them an excuse to keep "little old
lady" basic monthly rates down to about a fifth of cost in exchange
for ripping off blind anyone who has the temerity to pick up a phone
(or modem).
The "access charge" thing goes back to 1930 (Smith Vs. Illinois, US
Supreme Court), and is the FCC's conceptually reasonable (if screwy in
implementation details) way of recovering the fixed ("monthly") cost
of stringing miles of wire to all yer houses, when part of that cost
is legally Interstate and under their, and not the state's,
jurisdiction. They used to let AT&T Long Lines own that cost, but MCI
discovered that they could get away with using the wires without
paying for them. That's another story, though.
Local telephone rates haven't been deregulated. Before any screwy
"new" tariffs take effect, the state has to let them. But as long as
people scream out in self-righteous pain about paying their $2 monthly
"access" charge and act as if every hike in the rate *level* were
going to put them out of house and home, then telcos will be forced to
look elsewhere for revenue to cover the huge fixed cost of all those
wires.
------------------------------
Date: 12 Oct 84 10:52:05 EDT
From: dca-pgs @ DDN1.ARPA
Subject: Florida Wideband Fiber Optics Network
Microtel, Inc. of Boca Raton, FL, is an "intercity" (that is,
intra-Florida) carrier offering wideband network service via a Florida
state-wide FO network: LaserNet. Standard trunk size is 405 Mbps. The
net uses NEC eqpt with repeater spacing of 25 miles.
LaserNet offers VF, T1, T1C, T2, T3, and 90 Mbps (2XT3) interfaces.
Microtel is a partner in the Southeastern Communications(tele-)
Network (STN) and plans to expand the LaserNet to the Washington, DC
area within the next 2 years. The tariff tends to run about 30% less
than AT&T.
For more info: Mr. Charles Siperko VP, Operations Microtel, Inc.
7100 West Camino Real Boca Raton, FL 33433 305-392-2244
---------------------------------------------------------------
Best,
-Pat Sullivan
DCEC/R610
------------------------------
Date: Friday, 12 Oct 1984 11:23:55-PDT
From: molineaux%donjon.DEC@decwrl.ARPA
Subject: NOTES ON THE NETWORK
Notes on the Network may be obtained by calling the AT&T Customer
Information Center in Indianapolis at 800-432-6600.
The following books may be ordered from: AT&T Bell Labs,Room 1E 335
101 Kennedy Parkway,Short Hills,NJ 07078 or by calling AT&T at
201-564-2582.
Publication Yearly Fee Bell Labs Record $20 Telephony $30 Bell
System Technical Journal $35
------------------------------
From: tcs@usna.UUCP
Date: Fri, 12 Oct 84 17:10:40 EDT
Subject: AT&T ISN
Pat,
Take a look at the description on Computer Technology Review,
Summer 1984,pp 279, for a rough description of the basis of ISN. It
is a contention bus(es) system [3 busses actually] that avoids the
problem of collisions [ala Ethernet]. It is an 8.64Mbit/sec bus so
the claim of "fast response time because of the shortness of the net's
centralized transmission bus..." is a bunch of marketing hype.
Response time depends on system loading, etc. Besides, one of the
things you can do is decentralize it by connecting remote packet
controllers to the central node via fiber optic cables. It is really a
star configuration and they push the idea that it doesn't have
collisions like ethernet, but they don't tell you that the central
clock module in each packet controller is not redundant (sp?) so if it
dies, so does your network. They also don't (yet) have interfaces to
ethernet, etc. It is not clear to me how to ship IP packets across
this thing (assuming an interface to an IMP exists). But then again,
the only folks that have come here to talk have been more the
marketing type and not the technical type. Until I can talk with some
of the technical types I'll stay skeptical about its usefulness as a
data switch. It is supposed to use in-plant wiring (25pair cables to
your existing phones). Adding a box on the side of your phone (the
phone is digital - 19.2Kb data rate) allows an RS-232 connection
(19.2Kb data). The remaining bandwidth (out of 64Kb) is for
signaling. The folks who have been here have not mentioned host
interfaces (ie. high speed).
-tcs
Terry Slattery U.S. Naval Academy 301-267-4413
ARPA: tcs@brl-bmd UUCP:decvax!brl-bmd!usna!tcs
------------------------------
Date: Fri, 12 Oct 84 17:23:44 EDT
From: Jon_Tara%Wayne-MTS%UMich-MTS.Mailnet@MIT-MULTICS.ARPA
I run a BBS which is up only when I'm not using the machine (plug
- Detroit FIDO PCUTILboard - (313) 393-0527) and, for various reasons
would like to busy-out the line when I'm using the machine.
Now, I know that other people do this all the time, but I a bit
leary. I mean, the god-awful racket the phone makes when you take it
off the hook, along with the STERN message ("Please hang up. Please
hang up NOW!) lead me to beleive that, just maybe, Ma doesn't want me
doing it.
So, is there some "proper" way to busy-out a line? Obviously, I
don't want to pick up the receiver and hear the racket, so I need some
sort of a box (I presume a resistor across the line?).
------------------------------
Date: Sat, 13 Oct 84 07:19:30 pdt
From: (Mike O'Dell[x-csam]) mo@lbl-csam
Subject: AT&T ISN
It isn't a token ring at all. It is, however, DATAKIT in disguise.
The box in the closet is an adaptive time-division switch which
provides circuit switching. Connections are established by first
saying to the network (in effect) "Hello Central! Connect me with
number 46."
Just what you'd expect from the people that brought you cross-bar
relays.
-Mike
------------------------------
Date: 11-Oct-84 18:56:26-PDT
From: jbn@FORD-WDL1.ARPA
Subject: Recognizing Digital Signals
In a limited sense, long-distance telephone systems do recognize
data signals. Normally, voice connections over long paths, especially
long ones, pass through units called ``echo suppressors''. These are
basically voice-actuated switches that make the path half-duplex.
While the long-haul system is full-duplex, subscriber loops, being
only two wires, are not, and something must be done to prevent hearing
your own voice delayed by twice the propagation time of the circuit.
Echo suppressors perform this function but prevent full-duplex
communication.
Modems intended for use on the switched network turn off the echo
suppressors by issuing a tone at the start of the connection (this is
one of the functions of the standard modem answer tone) and as long as
some signal is transmitted thereafter, the modem suppressors remain
off. This makes the connection full-duplex and modems must be able to
cope with echo, which they typically do by assigning different
frequency bands to the originate and answer ends of the connection.
This is well-known and documented as a feature of the AT&T
system. As far as I know, the other vendors also obey the same
echo-suppressor control protocol.
John Nagle
------------------------------
Date: Sat 13 Oct 84 12:49:34-EDT
From: Alexander M. Fraser <T.ALEX@MIT-EECS>
Subject: Two modems on one phone line
I would like to get my two modems to talk to one another on
one phone line. I have a 1200baud internal modem for one of my
computers so unfortunately I can't directly connect them. Is there
any local/ non-charging ('cept for message units of course - they're
OK) number that will just keep the phone off of the hook, and be
silent? If not, how should I go about this (aside from using another
phone line I mean)??
Alex
------------------------------
End of TELECOM Digest
*********************