The Telecom Digest for December 04, 2010
Volume 29 : Issue 327 : "text" Format
Messages in this Issue:
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Date: Thu, 02 Dec 2010 19:44:45 -0800
From: Thad Floryan <thad@thadlabs.com>
To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org.
Subject: StarLAN (was: Re: Screw terminals)
Message-ID: <4CF867AD.9000108@thadlabs.com>
On 12/1/2010 5:49 PM, Scott Dorsey wrote:
> [...]
> Cat3 is just fine for the application; it's not as precisely made as Cat5,
> but it's a whole lot better than quad wire.
> [...]
CAT3 is full of surprises. Something not well known is StarLAN which in
today's parlance would be known as 1BaseT at 1Mbps and designed to work
over existing telephony infrastructures.
StarLAN was also the first implementation of Ethernet over twisted-pair
telephone wiring (http://en.wikipedia.org/wiki/StarLAN). As the
Wikipedia article states, StarLAN was patented by AT&T and also used by
Hewlett-Packard and Ungerman-Bass.
And used by me as you can see in this 4-page extract from the O'Reilly
"Managing uucp and usenet" book (now out of print):
http://thadlabs.com/FILES/OR_Mng_uucp+Usenet.pdf
which documents part of my (then) home office LAN circa early 1980s. At
that time I had both StarLAN and normal Ethernet over coax. The funny
thing is StarLAN actually was faster than "normal" Ethernet in real-
world testing. I still have 3 AT&T 3B1 (aka UNIXpc aka PC7300) systems
with both StarLAN and Ethernet cards installed; these systems also have
an embedded (on the motherboard) 1200 baud modem. With StarLAN, I could
and did connect my 3B1s to two Telebit T2500s on the LAN for UUCP and
everyday dialup use.
The StarLAN network was a significant breakthrough in affordable inter-
system communications with two major configurations:
1. per its name, a star, with a central hub serving many branches, and
2. with or without a hub, each branch serving up to 11 (IIRC) devices
electrically daisy-chained and extendable 3x with additional hubs
noting the hubs are named by AT&T as Network Extension Units.
"Devices" were manifold. Most common were interface cards for computer
workstations. Very common were StarLAN:RS-232 Network Access Units (NAU)
for adapting modems and other serial devices to StarLAN; I have many of
these and they were also very useful connecting computers with only a
serial console port or without other forms of networking.
The StarLAN hubs from AT&T were aka Network Extension Units (NEU) because
they could join multiple other branches and/or hubs to cobble-up very
large computer system and device arrays. What's really interesting is the
concept of a Media Access Control (MAC) address pioneered with StarLAN as
you can see in the rear-panel photo of one of my NAUs below.
Pictures of both a NEU and one of my NAUs taken a few minutes ago are here:
http://thadlabs.com/PIX/StarLAN_NEU_hub.jpg
http://thadlabs.com/PIX/StarLAN_NAU_front.jpg
http://thadlabs.com/PIX/StarLAN_NAU_rear.jpg
The white labels with black lettering are mine. The stamped labelling
on the rear panel of the NAU may be difficult to read; from left to right
the labels above each connector/button are: "DCE-RS232 A", "DCE-RS232 B",
RESET, POWER, IN, OUT, PHONE. The IN and OUT are for daisy-chaining in
a branch leg.
Date: Thu, 02 Dec 2010 19:59:09 -0800
From: Thad Floryan <thad@thadlabs.com>
To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org.
Subject: Re: Screw terminals
Message-ID: <4CF86B0D.5000801@thadlabs.com>
On 12/2/2010 7:40 AM, Adam H. Kerman wrote:
> [...]
> I don't recall seeing Cat3 at consumer electronics stores or home improvement
> stores ever. Was this a mass market consumer item in the days before Cat5
> became somewhat common? I do recall seeing Cat5 at Home Depot and Builders
> Square when big box home improvement stores were new but I don't recall
> that they offered a choice of Cat3 or Cat5.
>
> I assume I'd have had to buy from Graybar if I wanted Cat3, and I might
> not have been able to buy a reasonably small quantity!
> [...]
Here in Silicon Valley CAT3 was readily available at walk-in
consumer-type stores such as Halted, Haltek, Jameco, Quement, U-Do
Electronics, US Electronics, and even Fry's Electronics. There was
another store in Sunnyvale near the intersection of El Camino and
Sunnyvale-Saratoga whose name I've forgotten. San Mateo Electronics
http://www.smelectronics.com/ is another store I've been dealing
with since the late 1960s -- they have stuff most people don't know
exists (heh, try and find a caterpillar grommet in any store that's
walk-in and doesn't require a business permit to enter).
Sadly, most such stores are long gone along with the demise of the
great Heathkit company.
Date: Thu, 02 Dec 2010 22:24:40 -0800
From: Thad Floryan <thad@thadlabs.com>
To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org.
Subject: Verizon LTE Can Use the Monthly Data Allotment In 32 Minutes
Message-ID: <4CF88D28.20406@thadlabs.com>
In today's (2-DEC-2010) Slashdot:
http://mobile.slashdot.org/story/10/12/03/0019229/Verizon-LTE-Can-Use-the-Monthly-Data-Allotment-In-32-Minutes
Verizon's new 4G LTE network is so fast that you can use up
your entire 5GB in as little as 32 minutes. The 2010-era
speeds are soured by the 2005-era thinking on data plans.
Verizon has priced LTE pretty much like 3G to encourage data
sipping, not guzzling. As soon as you start using the latest
high-bandwidth Internet services, your whole month's allotment
can evaporate in no time. According to a test, the network's
speed maxed out at 21Mbps, which means that it takes only 32
minutes to smoke up the 5GB monthly data cap on the plan.
While the 21Mbps speed was hit on a low traffic network,
Verizon estimates you'll be able to get around 8.5Mbps with
a loaded network which still means that the cap can be
exhausted in about an hour and a half.
More info:
<http://www.pcmag.com/article2/0,2817,2373767,00.asp>
Date: Thu, 2 Dec 2010 14:40:12 -0800 (PST)
From: Tom Horne <hornetd@gmail.com>
To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org.
Subject: Re: US may disable all in-car mobile phones
Message-ID: <a1cfcda7-41ec-45fe-9853-f955bf21797b@y3g2000vbm.googlegroups.com>
[Moderator snip]
On Dec 1, 6:49 pm, tlvp <tPlOvUpBErLeL...@hotmail.com> wrote:
> Tom, by what exercise can we exorcise from you the devil in you
> that makes you repeatedly misspell "exercise" as "exorcise"? :-)
Death by spell checker. Point well taken.
--
Tom Horne
***** Moderator's Note *****
Is it possible to exorcise fat without exercise?
Bill Horne
Moderator
Date: Thu, 2 Dec 2010 14:45:51 -0800 (PST)
From: Tom Horne <hornetd@gmail.com>
To: telecomdigestmoderator.remove-this@and-this-too.telecom-digest.org.
Subject: Re: US may disable all in-car mobile phones
Message-ID: <a2356dee-6a9f-428e-ab02-9545ff3e3785@29g2000yqq.googlegroups.com>
On Dec 1, 3:26 am, "Bob Goudreau" <BobGoudr...@nc.rr.com> wrote:
> Tom Horne opined:
>
> > I wouldn't care one bit if traffic deaths were plummeting. If cell
> > phone use is causing even one death of a person who had no control
> > over the cell phone users actions then I want that use banned.
>
> Sigh. Time to trot out a "reductio ad absurdum" argument...
>
> [BEGIN R-A-A]
>
> There have been documented cases of criminals, not in moving
> vehicles, using their mobile phones to dispatch hit-men to murder
> innocent victims who had no control over the cell phone user's
> actions. So I guess we will need to ban cell phone use by stationary
> callers as well as by those in vehicles.
> For that matter, there have been numerous cases of similar murder
> orders communicated by old-fashioned land-lines. So I guess
> non-mobile phones will also need to be banned. Anything to save a
> life, after all!
>
> [END R-A-A]
>
> The problem of all those "if it saves even one life..." type of
> arguments is that they rarely acknowledge that there might be costs
> along with the purported benefits. Those costs are not even purely
> financial, but may include opportunity costs in time and even in
> lives. A frequent example of unintended consequences is the field of
> aviation: new safety measures have to be carefully considered
> because if they raise the cost of flights too much, or add enough
> new travel delays, they will end up marginally increasing the number
> of people who choose to drive instead of fly, inadvertently causing
> more deaths on the road than they prevent in the air.
>
> So by all means, state the case for trying to ban all communication
> from phones moving at more than X miles per hour (for some value of
> X). But be prepared to quantify the costs as well as the benefits,
> so that we can weigh the tradeoffs. We are all aware of reports of
> crashes caused by distracted driving. But many of us have also heard
> of drivers phoning in reports of drunken drivers. In my own area, we
> have had several cases of terrified women desperately calling police
> to report that they were being chased at high speeds by murderous
> estranged husbands/boyfriends. All of these positive uses of phones
> in moving vehicles would disappear under a blanket ban. Are those
> losses outweighed by the benefits? I don't know -- but I don't think
> you do either. The burden of proof is on those proposing to change
> the status quo. Most people can be swayed to your side if the
> evidence is there, so have at it. But be prepared to show your work.
Bob,
[Moderator snip]
I have made it very clear that banning non-emergency cell phone use
can be done without banning emergency use. With emergency use still
possible, what other defense can you come up with for the unique
distraction from the driving task that is a driver's participation in a
full duplex telephone conversation?
--
Tom Horne
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