telecom@ucbvax.ARPA (01/24/85)
From: Jon Solomon (the Moderator) <Telecom-Request@BBNCCA>
TELECOM Digest Tue, 22 Jan 85 21:28:25 EST Volume 4 : Issue 148
Today's Topics:
PacBel leading the way -- yet again.
help with RJ-41S and RJ-45S
Communications Forum Seminars
MIT Communications Forum Seminars
Time-segment speech scramblers
Satellite communications: Portable Earth station
----------------------------------------------------------------------
Date: 16 Jan 1985 14:38-PST
Subject: PacBel leading the way -- yet again.
From: the tty of Geoffrey S. Goodfellow <Geoff@SRI-CSL.ARPA>
To: Telecom@MC
The following insert came in the bill for the leased line that
goes SRI and my residence:
NOTICE OF FILING
APPLICATION TO
DISCONTINUE TIME
PUBLIC ANNOUNCEMENT
SERVICE AND CONTINUOUS
TIME ANNOUNCEMENT
SERVICE AND TO PROVIDE
TIME ANNOUNCEMENT
ACCESS SERVICE
On November 7, 1984 Pacific Bell filed with the California Public
Utilities Commission a request to withdraw the existing Time
Public Announcement Service and the Continuous Time Announcement
Service. In addition Pacific Bell has proposed that the current
Time Public Announcement Service responsibility be turned over to
a private information provider. the proposed charge would be 20
cents per call.
A copy of the application, 84-08-049, and related exhibits will
be furnished upon written request to: Pacific Bell, 140 New
Montgomery Street, San Francisco, CA 94105 or at the offices of
the California Public Utilities Commission.
Requests for information may be directed to the Commission
Offices at 350 McAllister Street, San Francisco, CA 94102 or 107
South Broadway, Los Angeles, California 90012.
--end of insert--
Question: I wasn't aware there were two different services, as
they implied in the insert, i.e. "Time Public Announcement
Service" AND "Continuous Time Announcement Service". Anyone know
what's the beef here?
Next think you know, the Weatherperson (936-1212) will be a thing
of the past as well!
g
------------------------------
Date: Thu, 17 Jan 85 11:37:04 est
From: Mark Weiser <mark@tove>
To: telecom@mit-mc
Subject: help with RJ-41S and RJ-45S
What can anyone tell me about RJ-42S and RJ-45S telephone connections?
I'll tell you what I know.
I just bought a couple of Anderson Jacobson 4800 baud modems for use
over regular 2-wire telephone lines. However they arrived with,
instead of the little 4 connector modular plug (RJ-11C), with an
8-wire modular plug into the phone system, which they call an
RJ-41S or RJ-45S (I don't know what the difference is). They claim
the phone company must come out and install the corresponding 4-wire jack.
Here is what they say about using the RJ-11S:
"Connecting the modem to the telephone line with an RJ-11C jack
is not recommended, although it may work under certain conditions.
An RJ-11C voice jack requires a 4-wire telephone cable, not supplied
with the AJ-4048 modem."
Actually not only do they not supply the 4-wire cable, but they don't supply
anyplace on their modem where the 4-wire cable could plug in.
I also think I am going to need to get myself a phoneset with an 8-wire
connector since the AJ doesn't autodial. Are these available?
My questions are:
A. Is it likely to be a big deal or a little deal for the phone
company to install that 8-wire jack in my house? Are the 8 wires
in the wall somewhere or does a major restringing occur? (I would
guess from the descriptions of wires 7 and 8 below that they are
just a volume control from the phone company built into the box.)
B. Are there adaptors available to go from 8-wire to 4-wire connectors
and back? The quote above implies it is somehow possible.
C. What is the real difference? What are the circumstances under
which RJ-11C will not work but RJ-41S will?
Thanks for any and all help.
By the way, the 8 wires are identified as follows (in the AJ manual):
1. no connection
2. no connection
3. Mode indicator. Selects voice or data mode depending on state of
telset exclusion switch (or other control).
4. Ring. One side of telephone line.
5. Tip. Other side of telephone line.
6. Mode Indicator Common. Ground.
7. Programming Resister. Resistor (on data block) used to
control modem transmit level.
8. Programming resistor common. Return side of PR signal (7. above).
7 and 8 are identifed as: "Passive or isolated signal", and none of the
rest are, whatever that means.
------------------------------
Date: Fri, 18 Jan 85 21:31:40 pst
From: newton2%ucbtopaz.CC@UCB-VAX
To: telecom@UCB-VAX
This is a renewed request for discussion/comment/pointers on the
subject of speech scramblers which work by temporily shuffling blocks
of speech.
If we assume the underlying cryptography to be secure (i.e. the generation
of scramble-sequences throughout the message cannot be anticpated wihout
the key), what are the techniques for cracking the system by direct assault
on the analog scrambled signal? How quickly can this be done- Real time?
I assume a digital random access memory- no clues from the differing noise
level along the length of an analog shift register. However, there might
be clues from the excitation of the (known) impulse response of the band-limited
voice channel, or by endpoint matching of segments. And of course the cleartext (voix humaine) has some known
characteristics.
Is such a scrambler of *any* value against a determined opponent-- i.e.,
might it provide at least some time-limited security or require such special
equipment for routine cracking that the use of large numbers of such scramblers
might overwhelm a particular opponent (not knowing which messages were high-value?)
I'd greatly appreciate any discussion of this, public or private.
Thanks-
Doug Maisel 415 549-1403
------------------------------
Date: Mon, 21 Jan 85 17:40 EST
From: Kahin@MIT-MULTICS.ARPA
Subject: Communications Forum Seminars
To: Bartl@MIT-MULTICS.ARPA, RSKennedy@MIT-MULTICS.ARPA,
Prospects for Leased Access
February 7, 1985
Richard B. Smith, President, Satellite Program Network
Kathy Garmezy, Labor Institute of Public Affairs
William Finneran, Chairman, New York State Commission on Cable
Television
The new cable legislation provides that systems with 36 or
more channels must make time available for commercial leasing at
a "reasonable" fee. Some have argued that such laws deprive
cable operators of First Amendment rights. Others have argued
that a full "separations policy" is necessary to maximize
diversity.
This seminar will look behind the longstanding policy debate
to assess the demand for leased access. Who is willing to pay
for it? At what price? What are the opportunities for national
packaging services? Will leased access programming offer
anything different? Or will it simply substitute for public
access or special programming services?
Software Protection and Marketing
February 14, 1985
Ronald Rivest, MIT Laboratory for Computer Science
Wayne Chou and Richard Erett, Software Security, Inc.
February 21, 1985
Michael Tyler, Datamation
Todd Sun, Multimate International
Representative from Lotus Development Corporation
The mass marketing of personal computers has created a large
market for software -- and with it, unauthorized copying on a
large scale. Two special seminars will look at the problem of
unauthorized copying: What technologies can be used to minimize
it? How big is the problem and how does it affect marketing
strategies? Are technological and marketing solutions adequate?
The first seminar will look at different technologies used to
prevent copying. The second will consider the advantages and
disadvantages of copy protection in the marketplace and
strategies such as user registration and bundling of support
services.
The Multivendor Computer Networking Zoo
February 28, 1985
Paul Green, IBM
The difficulty of interconnecting networks or network
components when they obey different architectures inhibits the
growth and flexibility of computer communications. Two ways to
alleviate the problem are: to adopt a standard architecture for
all nodes in the network; or to provide conversions at suitable
points in the network and at the level of a suitable
architectural layer. The first approach is most unlikely to
succeed. The seminar will focus on the second approach. First
some details of the "mapping" that must take place at the point
of discontinuity will be reviewed. Then the roles of enveloping,
substitution, complementing, and conversion will be described.
Prognosis about the possible existence of a general methodology
for synthesizing the mapping leads to the final topic -- the role
of Open System Interconnect as a solution.
Changing Communications Technologies: Learning from the Past
March 7, 1985
John McLaughlin, Harvard Program on Information Resources Policy
JoAnne Yates, MIT
Richard John, Business History Review, Harvard
New communications technologies have profoundly changed
communications practices and communications industry structure --
and the structure of other businesses. Mapping these changes
over two centuries reveals an interrelationship between broad
structural trends and the development of particular products and
services.
One trend is the emergence of systems that combine products
and services -- and that combine content and conduit. Another is
the cycle from competition to monopoly and back to competition.
An especially important question is how advances in
communications technology affect the size and structure of
business users.
Unrecordable Video
March 14, 1985
Andrew Lippman, MIT
John Woodbury, National Cable Television Association
Speaker to be announced
Although motion picture producers depend increasingly on
revenue from television and home video, the spectacular growth of
videocassette recorders has provoked fears that much potential
revenue will be lost. The Electronic Publishing group of MIT's
Media Laboratory has developed a way of generating television
transmissions that can be viewed but not taped. This seminar
will present the technology, and industry representatives will
discuss the possible effects on distribution practices.
------------------------------
Date: Tue, 22 Jan 85 13:12 EST
From: Kahin@MIT-MULTICS.ARPA
Subject: MIT Communications Forum Seminars
To: Telecom@USC-ECLC.ARPA, Human-Nets@RUTGERS.ARPA,
MIT Communications Forum seminars are held on Thursdays from 4:00 to
6:00 in the Marlar Lounge (Bldg. 37-252, MIT, 70 Vassar St., Cambridge)
------------------------------
Date: Fri, 18 Jan 85 21:33:05 pst
From: newton2%ucbtopaz.CC@UCB-VAX
To: Telecom-Request@BBNCCA
Subject: Time-segment speech scramblers
This is a renewed request for discussion/comment/pointers on the
subject of speech scramblers which work by temporily shuffling blocks
of speech.
If we assume the underlying cryptography to be secure (i.e. the generation
of scramble-sequences throughout the message cannot be anticpated wihout
the key), what are the techniques for cracking the system by direct assault
on the analog scrambled signal? How quickly can this be done- Real time?
I assume a digital random access memory- no clues from the differing noise
level along the length of an analog shift register. However, there might
be clues from the excitation of the (known) impulse response of the band-limited
voice channel, or by endpoint matching of segments. And of course the cleartext (voix humaine) has some known
characteristics.
Is such a scrambler of *any* value against a determined opponent-- i.e.,
might it provide at least some time-limited security or require such special
equipment for routine cracking that the use of large numbers of such scramblers
might overwhelm a particular opponent (not knowing which messages were high-value?)
I'd greatly appreciate any discussion of this, public or private.
Thanks-
Doug Maisel 415 549-1403
------------------------------
Date: 22 Jan 1985 1135 PST
From: Richard B. August <AUGUST@JPL-VLSI.ARPA>
Subject: Satellite communications: Portable Earth station
To: telecom-request@bbncca
SUITCASE COMMUNICATOR
The equipment is a portable communications system designed
to relay messages over long distances by satellite. A joint
development of NASA's Ames Research Center, Mountain View,
California, and General Electric Co., Schenectady, New York, it
consists of a collapsible antenna and a computerized transceiver,
a terminal for sending and receiving messages. The whole system
fits into two Pullman-size suitcases and can be powered from a
conventional outlet or a vehicle's battery.
Use of satellite relay permits transmissions in almost any
terrain, even in areas where mountains block normal line-of-sight
transmission. In intitial tests, the relay spacecraft was NASA's
Applications Technology Satellite direct broadcast satellite.
With ATS-3, an operator anywhere in North or South America and
most of the Atlantic and Pacific Oceans can communicate with
fixed Earth stations in those areas. If a network of compatible
satellites were available, the system could be used globally.
The principal use envisioned is communications in disasters
and other emergencies where it is necessary to get short but
vital messages out of the emergency area. The 1980 eruption of
Mount St. Hellen illustrated the need for rapidly deployable long
distance communications not dependent on wirelines, because such
lines are often destroyed in disasters. Another application is
long-range communications between transportation vehicles and
their dispatch offices. In a seven-month test concluded last
year, drivers of Smith Transfer Corp. cross country trucks
exchanged information via satellite with their dispatchers in
Staunton, VA. The drivers reported excellent communications
except on brief occasions where trees or overpasses blocked line-
of-sight transmissions. Such a communications system offers
advantages to the trucking industry in keeping track of
equipment, improving maintenance schedules, avoiding improper
routing and reducing theft losses.
The system is alphanumeric, meaning that messages are sent
and received in letters and numbers. The operator types a message
on a keyboard, then transmits it to the Earth station by punching
a single key. Another keystroke enables him to receive messages
stored at the Earth station. The terminal can be set up in two
minutes. The antenna unfolded and pointed toward the satellite;
the proper direction and elevation are available from a simple
chart.
ATS-3 is 17 years old and nearing the end of its useful
life, but if enough public service and commercial applications
are found, the system could be redesigned to work with other
satellites. Mobile Satellite Corp., King of Prussia, PA, plans to
build and operate such a satellite; the company has filed an
application with the Federal Communications Commision for a
frequency allocation.
------
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End of TELECOM Digest
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