Daily Notes

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]