Private Lines
About Private Line

Private Line covers what has occurred, is occurring, and will ocurr in telecommunications. Since communication technology constantly changes, you can expect new content posted regularly.

Consider this site an authoritative resource. Its moderators have successful careers in the telecommunications industry. Utilize the content and send comments. As a site about communicating, conversation is encouraged.


Thomas Farely

Tom has produced since 1995. He is now a freelance technology writer who contributes regularly to the site.

His knowledge of telecommunications has served, most notably, the American Heritage Invention and Technology Magazine and The History Channel.
His interview on Alexander Graham Bell will air on the History Channel the end of 2006.

Ken Schmidt

Ken is a licensed attorney who has worked in the tower industry for seven years. He has managed the development of broadcast towers nationwide and developed and built cell towers.

He has been quoted in newspapers and magazines on issues regarding cell towers and has spoke at industry and non-industry conferences on cell tower related issues.

He is recognized as an expert on cell tower leases and due diligence processes for tower acquisitions.

January 04, 2006

Part C

As their mobiles got smaller and smaller, Motorola cellular telephones featured three major design changes, leading up to the StarTac design of today. The bag, the brick, and the flip proved extremely popular.

Click here for a larger image of the bag phone

A transportable or luggable phone, the bag phone contained a heavy cellular transceiver with a large battery enclosed in a leather bag. Since battery life wasn't good, most people plugged the unit into a car's cigarette lighter and used it while driving. Power output was twice that of the brick, the hand-held cellular phone that borrowed its name from Motorola's first Handie-Talkie. Dwarfing any present hand-held, except perhaps satellite phones, the brick's battery itself was larger than most cell phones on the market today.

Click here for a larger image of the brick phone

When the first digital networks were built Motorola introduced the flip phone, part of their Personal Digital Communicator Series. It could work in analog or digital mode. Many are still being used although the StarTac, introduced in 1996, and now the MicroTac, have since replaced the original flip phone.

Click here for a larger image of the flip phone

For a look at how Ericsson cellular telephones evolved, click here

We discussed how reducing radio size and weight in World War II was less important than the modulation technology hand-helds eventually used: F.M. Today, as every company produces smaller and smaller radios, the technology used to transmit information is the most important development: C.D.M.A. or code division multiple access. Sometimes called spread spectrum or frequency hopping, C.D.M.A., puts bits and pieces of several calls on different frequencies. It's the most efficient technology, allowing more calls in the same spectrum than older digital systems. And where did CDMA start out? Well, you may have guessed the answer.

Spread spectrum was first used during World War II to prevent signals from being jammed. By rapidly changing frequencies the Allies found the Germans could not interfere with their transmissions. This immunity to interference is yet another reason for C.D.M.A.'s great popularity, indeed, the entire wireless world is embracing this technology. When GSM based systems evolve they will use it, as well as the next generation of I-Mode. This new yet old operating method reveals again the important and continuing link between civilian and military communications.

Patent illustration 2,292,387, for a Secret Communication System, utilizing spread spectrum. Co-filed by the movie star Hedy Lamar

Article Index

Recent Posts

Powered by
Movable Type 3.2