Selected Daily Notes Archive (Home Page has current notes)

Oldest (Page 1) to most new (Page 52)

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15) (16) (17) (18) (19) (20) (21) (22) (23) (24) (25) (26) (27) (28) (29) (30) (31) (32) (33) (34) (35) (36) (37) (38) (39) (40) (41) (42) (43)(44) (45)(46) (47) (48) (49) (50) (51) (52)

September 23, 2005

Hendrik Daehne is a computer science student at the University of Hamburg. He's currently writing a paper about security issues in C450 and AMPS for his network security course. I thank him very much for contributing these hard to find details about Germany's C-Netz.

Hi Tom,

Great site!

I just saw your table about "Analog or First Generation Cellular Systems". ( http://www.privateline.com/PCS/history9.htm ) I can offer you some additional information about "C-Netz": "C-Netz" or "Netz C" is German for "network C" and stands for the third mobile phone network (succeeding the networks A and B) of the country. The German C-Netz was based on the C450 technology, the Austrian C-Netz on NMT450 (hence, the table is not correct about Austria).

C450 was developed by Siemens around 1980. It was -- to my knowledge -- the most advanced analogue system in the world. Some of its features included non-audible in-band signalling (using analogue audio compression with data bursts in the resulting time slots), speech scrambling (band inversion) and incoming and outgoing waiting queues for when the network is congested. Signalling was completely digital (no tones like SAT).

The German network started with magnetic stripe cards in 1985, followed by memory chip cards in 1988 and eventually by microprocessor chip cards in 1989. These microprocessor cards had a phone number memory and could be used with public card payphones (billed on your cellular account). They also introduced security features like PIN codes and authentication (using challenge-response algorithms). As you've already mentioned on your site, the nearest cell tower was determined by signal delays rather than by field strength (the system supported both ways). For this purpose the network was completely synchronized.

The network in Germany started trialing in 1985, and was launched
commercially in 1986. It reached around 800.000 subscribers in 1993.

The networks in Portugal (1989) and South Africa had much lower customer numbers. All networks were shut down around 1999/2000. Subscriber equipment providers included Siemens, Alcatel, AEG, Philips, Motorola and Nokia.

The phone I attached was developed by Technophone in the UK, but sold under various brand names starting in 1988 (the images are from flyers released by "DeTeMobil GmbH", which are now known as "T-Mobile Germany").

Greetings from Hamburg/Germany,

Hendrik

[Picture One] [Picture Two]

September 16, 2005

Excellent article below. Read the whole piece before it is pulled off the web:

Hardware Warriors

An unusual link to Silicon Valley's cultural and technological history, the Electronics Flea Market is practically a subculture in itself

By Russell Mahakian

IF ONE MAN'S JUNK is another man's treasure, then the trucks and vans arriving before daybreak at De Anza College's parking lot for the Electronics Flea Market are carrying either cabs full of garbage or mechanical wealth beyond a gearhead's wildest dreams.

A novice may be left dumfounded by the bins overflowing with metal machines, some with '50s sci-fi knobs that look more like props from Forbidden Planet than devices with any practical use.

Look closer, though, and you'll find a hands-on history of electronics and technology in Silicon Valley. Browsing through boxes of old gear and electronic cables provides a clear view into the innovative thinking and social scene that made this valley ripe for a tech explosion.

"This stuff was our Super Mario Bros. There is real history in this stuff," says one flea market regular, pointing to a Heathkit mulitmeter.

(continues here, external link --->)

September 14, 2005

I'm returning to hardcopy publishing after 10 years. My new venture will be California Rockhound. This is on-demand publishing, printing copies as needed from my home. It will be a very different magazine; I wish I could describe it better but I have only a third produced so far.

It's really a chronicle of discovery, wandering in the wilderness, looking for stuff. If I find gold, great, if not that, quartz crystals, if not that, gem quality rocks and minerals, if not that, a set of deer horns, if not that, the flight of a Bald Eagle, if not that, well, being outside, exploring. I'll provide road directions and GPS coordinates for every find I make or point of interest. And there will be an information package: maps, BLM pamplets, Chamber of Commerce handouts, that accompanies each magazine, so you will be able to make the same trip that I do. If you can't go to an area I describe you will have so much information to read that you'll feel like you're driving or hiking with me. Without putting up with me saying things like, "Pull over, I need another Diet Pepsi." Or, "Pull over, I need to put more ice on my poison oak." Or, "Will you please follow me on this rope line. The slope isn't that steep." :-)

First issue should come out in January. Visit the site if you like: http://www.californiarockhound.com (external link)

E-mail me from there if you want to sign up for further updates. Thanks, Tom

September 13, 2005

Q. Where can I learn to repair cell phones?

A. Tom Farley here. There isn't anywhere to learn since most aren't repaired. Cell phones now use surface mount components, which means parts can't be easily replaced from their circuit boards. The days of discrete components are long gone. Also, since the price of cell phones is so low, they have become disposable, even with the most expensive models. It's cheaper to ship the customer a new phone. What carrier wants to take in an old phone, ship it to the manufacturer, have Samsung or Motorola chase down a defective transistor or diode, replace it, put the phone back together again, and then ship it back? Geoff Fors contributes the final word:

"Well, you are right. Cell phones are disposable. Most are manufactured in China on robot machinery and most of the parts are not available here anyway, nor are the schematics and technical diagrams. There is no provision whatever for repairing them anymore. The last phones that anybody tried to offer repair on were the Motorola 'Flip-Phone' Micro-Tac models of 1987-89, and those had to be shipped to Motorola for service. That's why you'll find trash bins at Office Depot and elsewhere with signs on them saying 'deposit cell phones and empty printer cartridges here.'"

"Two way radio repair is a dying art. That's why so many truly wonderful two way radios are for sale on eBay for $5 to $10. There is no one left in the industry to repair them or understand them. They just change modules or boxes. PG&E in California closed down its radio repair shops back about1992-93 and today just ships the whole thing back to the manufacturer, which is the wave of the future. So many businesses have dropped two way use in favor of Nextel handsets that there isn't much business left for traditional two way. They are now paying the price for that in Louisiana and Mississippi where nothing worked (or works) when it was needed the most."

"I recently saw a job ad on one of the newsgroups I subscribe to, for a radio shop supervisor with Texas D.O.T. in Wichita Falls. They wanted someone to be a one-man-band familiar with everything from computers through microwave multiplex including component level service, preferably with a college degree, yet they wanted to pay 'about' $ 2500 per month. That's another reason nobody wants to get into the radio communications business. Considering that it was a salaried position without overtime, I expect the guy will be working for about 3000 hours a year, which works out to $10 an hour before taxes, less than many unskilled labor jobs. There's no future in civilian radio repair."

September 10, 2005

Q. Would the Ambassador Hotel in Los Angeles used a switchboard in 1968 for its incoming and outgoing telephones calls to connect to the rooms?

A. (Tom Farley) Most probably, yes, they would have had a manual switchboard well into the 70s. Computerized telephone switching for companies was still quite expensive at that time. And the lack of personal service would have been a strike against the equipment at a first class hotel. That's my best guess, I would be amazed if this wasn't true.

A. (J.R. Snyder Jr.) (internal link) The first paid job I had was working at the Scottsdale Hilton when I was 14, answering the manual cord switchboard for a few hours after school. My mother was the front offfice manager. They needed help while people were checking in, I got paid something like 50 cents an hour.

About four years later, around '73 or so, I was already at the phone company and my mother had become the General Manager (quite a coup for a woman) of the entire property. The hotel, owners, management, staff and regular guests, were in quite a tizzy about the old switchboard being taken out.

They were replacing it with a direct to the rooms PBX {private branch exchange, ed.] and it was sort of like them taking exchange names away. A lot of people thought it was impersonal. My mother's point of view was pure business (my mother is English and has little romance for these things) and thought the whole uproar was ridiculous. She didn't have to pay two switchboard operators and time and charges were automatic and almost indisputable.

I remember Zsa Zsa Gabor being cheap, cheap, cheap. She demanded flowers and fruit baskets (gratis) and denied every call she ever made and they just wrote them off to get her out of the lobby. The hotel Bob Crane was murdered in, which was pretty classy at the time, was about a mile away.

I do remember as a kid when we travelled a lot hating to have to use the phone because you had to go through a switchboard operator who KNEW you were "that kid" in XYZ room with his parents.

September 7, 2005

Q: In GSM, does voice traffic between mobiles in the same cell site pass through the MSC? I'm not concerned about signalling information.

A. (From different contributors) GSM routes all calls through the MSC, just like AMPS (internal link). That's not the case with CDMA. Not surprising -- technology evolves, and IS-95 (CDMA) is newer than GSM. In the same way, UMTS, evolved CDMA, came after IS-95 and hence operates more like IS-95. Again, not surprising.

In a CDMA network a call as you describe would not route through the switch. Any calls going through the switch must pass through the vocoder to be converted to ordinary landline type voice traffic. Every time we do that, we lose quality, of course. Therefore, for a mobile to mobile call in the same BSC, the voice traffic does not route through the switch, but instead is simply routed to the other mobile so the voice doesn't pass through the vocoder any more than necessary.

August 27, 2005

E-mail them at: auditel@auditelinc.com

August 10, 2005

Good information and memories from Bill Demakakos on his experiences as one of the first male operators at AT&T's New York International Operating Center. Many pictures. Click here to go there. (internal link).

July 25, 2005

Changes coming soon

Ken Schmidt of Steelintheair.com will soon own privateline.com. Most of the content and features here will stay the same. I'll still answer my telephonic related e-mail and update certain pages, but for the most part I will leave the site to Ken. I hope all privateline.com readers continue to send comments, corrections, and memories. It's these contributions that have helped this site become popular and useful.

As for me, I will focus on writing more hardcopy articles for publication, such as the mobile telephone history piece I recently completed for Teletronik. I have other things I want to spend more time on as well, such as my interests in prospecting and rockhounding. I'll still be around, though, and I hope you will too. Feel free to contact me (e-mail link). Best, Tom

June 12, 2005

Q. Did you know the 'G' in LG Telecom stands for Goldstar?

A. From Mark van der Hoek (internal link):

Woah! So THAT is what happened to Goldstar? There's a cellular story here:

Way back when I was installing for a living, the biggest Authorized Agent for PacTel Cellular was a company called Cellular Communications Corp. My history in the biz has been interwoven with these guys. Remember that my first exposure to cellular was when that little two-way shop arranged for me to do a ride-along of some of those new-fangled cellular phone installations? That was for CCC, Irvine, their first of about 5 stores. I was service manager for the Colton (San Bernardino) branch later, and the branch manager for the Irvine store was a guy called Marv Madsen. He was the founder (after CCC was bought out/shut down) of his own Authorized Agent store in Riverside, and hired me to be his service manager when he opened his store. From there I went to work for PacTel (later to become AirTouch). All of that spans about 7 years, and during that time I worked at the Carson branch, and did a lot of freelance installation work for all the branches, primarily Irvine.

Now, I said all that to say all this. CCC was the company that invented the cellular call box. GTE later bought them to get that business, then about a year later (after a court ruling made reselling much less profitable) shut down the retail side. (Happened during the time I was service manager at Colton.)

They got pretty big on the retail side of things, and got to thinking pretty well of themselves. In fact, they decided to have a phone brand all their own. They bought the rights to a British made phone called the Walker. A huge phone, but indestructable. The truckers LOVED them. Lots of room in an 18 wheeler cab, so the size was no problem. Oh, but in a Mercedes? Not only was the control head huge, it CLUNKED with a nice metallic sproiiiing sound when you hung it up. Not good.

So, the intrepid service staff at the Irvine branch were tasked with finding an overseas company that could produce the Walker with a decent sized control head. The prototypes arrived just about the time GTE was taking over. The new management said, "Our own phone? We control the price and markup? GREAT! We're ordering 10,000!" Of course, the service folks (who later worked at AirTouch) were left screaming "NO!!!!!!!!!!!!!!!!!!" to a blank wall. All management heard was "our own phone brand". They didn't/wouldn't hear "unreliable", or "piece of junk", or "absolute trash" or "metal filings floating around inside the transceiver case".

It was a disaster.

Yep. It was made by Goldstar.

You knew there was a point behind this ramble, didn't you?

[Editor's note. My first cell phone was an original Walker installed in my company truck. This was around 1986. You could hammer nails with the control head or handset. The only thing to compare its toughness to are public payphone receivers. Yes, it was that tough. Oh, that nice metallic sproiiiing sound? Actually, it settled into its cradle with a very assuring CLUNK. Tom.)

Selected Daily Notes Archive (Home Page has current notes)

Oldest (Page 1) to most new (Page 52)

(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15) (16) (17) (18) (19) (20) (21) (22) (23) (24) (25) (26) (27) (28) (29) (30) (31) (32) (33) (34) (35) (36) (37) (38) (39) (40) (41) (42) (43)(44) (45)(46) (47) (48) (49) (50) (51) (52)

Free Telecom Magazines through TradPub.com. Click here to go there