Viewpoint: Wireless Computing

Pagers, PDAs and H/PCs

Paging Comes to PDAs and Handheld PCs 

By Andrew Seybold

Palm/3Com folks now have a one-way paging option available for the Palm Pilot and Professional. (However, it is not compatible with the Palm III). Motorola built the pager into a module that slips into the space designed for additional memory. The pager module includes more memory, an upgrade of the Palm operating system, and the Motorola FLEX OS as well as a pager.

The pager is not simply slapped onto a Pilot. The two devices work well together--calendar updates can be received and placed in the calendar, and the displays of numeric pages from people listed in the phone book include the name of the person associated with the phone number.

Motorola, 3Com, and PageMart have done a great job integrating these devices. PageMart coverage is robust, and the product does not break the Pilot's form factor. There will be similar devices available for Handheld PCs and Palm-size PCs designed to work with the Windows CE OS. How important are these products? How good is the coverage? Most importantly, how much will the service cost? This month we will address all of these issues.

One-way paging networks

• One-way paging networks were designed from the ground up to provide strong in-building penetration.
• It is simpler to provide in-building coverage for one-way communication than it is for two-way because the system transmitters can transmit at much higher power levels than mobile device transmitters. Most one-way paging transmitters have an output power of between 100 and 300 watts, which is then increased by the antenna system to provide an effective radiated power (ERP) of 1,000 to 3,000 watts or so. By comparison, most cellular and PCS systems employ base stations with output power measured in watts as opposed to hundreds or thousands of watts.
• Most paging systems use a technique called "simulcasting." The system sends the page to many base stations at once, and all of these base stations transmit at the same time. Simulcasting systems have been engineered in such a way that there is an additive effect in the coverage area.

Types of Paging Information

Paging systems today provide one-way data streams that either display only numbers (numeric-only), or letters and numbers (alphanumeric or "alpha"). Today, most paging customers carry numeric pagers, but alpha paging is growing rapidly. Alpha pagers are ordinarily set to receive up to 256 characters per message. However, some paging carriers prefer to limit users to 80 characters per message, primarily because of the amount of traffic on the network. Longer messages take more airtime, delaying other pages while they sit in a queue until the channel is clear.

Types of Paging Systems

There are four basic types of paging systems in use today: private, local, regional, and nationwide.

• Private systems ­- These are the most commonly used to provide paging coverage to employees within a certain geographic area or inside a building. They are purchased by a company, installed at its own location, and operated on a frequency assigned by the FCC for private system use.
• Local paging systems -­ These cover a specific area or city, and are most often operated by local independent providers that have usually been in the paging and mobile communications business for a long time. Local systems usually offer good coverage within the geographic region they are intended to cover. Many of these providers are selling out to larger paging carriers because they are finding it difficult to compete, even on a local basis.
• Regional systems -- There are two types of regional paging system providers. The first, as with the independent local provider, has built its own system out over time and has expanded it beyond the city to cover a region. For example, a regional system might cover the San Francisco/Oakland/San Jose metro areas and the surrounding suburbs. The second type of regional system is actually a nationwide system that is segmented into regions so that the provider can offer regional as well as nationwide services. With most of these systems, you can sign up for regional coverage and add another region or nationwide capability on the few occasions when you travel outside your home area.
• Nationwide systems -- The major paging carriers have a nationwide footprint. Some also offer coverage in other parts of the Americas and into Asia. Nationwide one-way paging service rates are higher because the paging operator must turn on, or "fire," every transmitter in the network for every nationwide page. This is the only way to be reasonably certain that you will receive the page since the network has no way of knowing where you are at any given moment.

Under these conditions, both a regional and a nationwide single-channel paging company would have about the same capacity. For this reason, most nationwide systems operate on multiple channels.

Additional services available

Several companies, such as AirMedia Live, offer services that provide users with news, weather, and sports in addition to email headers and other customer-specified information. There are also software packages that will monitor a user's desktop and push messages out to the pager. For example, a shareware product called Internet Email Forward is available from http://www.devnetsoft.com on the Net.

Other companies such as Visto, and General Magic with its Portico service can provide users with calendar updates, messages, and email headers. Depending on the information that a customer wants to receive, such services can be programmed to use the pager as an alert device for a wide variety of message types including faxes, voice mail, and email. One advantage to using "smart" software or services is that you can restrict the amount of information that is sent to your pager. Most go so far as to "strip" unneeded header information so that fewer characters are sent out over the air.

Prices vary, but it's expensive

Messages sent out over the paging system are "pushed" to the user from a variety of systems, including the Internet, desktop computers, telephone keypads, and messages dictated to a service over the phone. The pricing models in the sidebar are based on direct access to a paging service. These other methods of pushing messages only add to the expense of using paging.

As can be seen from sidebar, using one-way paging and PDAs to receive calendar updates and email headers is not very economical. In fact, it would be less expensive in most cases to use a cellular voice phone and input the updates manually.

If one-way paging carriers have any interest in providing information services to PDA/PC Companion users, I believe that they must establish a different pricing model for such services. The problem with this is that it will be difficult to maintain one set of prices for paging device users and another for PDA users--especially since pricing for one-way paging is based on the fact that the systems have a finite capacity. Paging carriers want to maximize their income for each channel. When users on the channel receive more data each day, fewer users can be accommodated.

Another problem that has to be considered is that all one-way pages are sent immediately when they are received by the system. Because the system does not know whether you are out of coverage or whether you received the message, you can miss one or more pages. The only way to determine whether you have missed a page is to be aware of the sequence numbers sent out by most paging carriers. If you receive page 1 and then page 4, you know that you have missed 2 and 3. While you can generally call in and retrieve missed pages, you must first be aware that they were missed.

PC Companion pagers coming soon

Even with the high cost of one-way paging services, expect to see more computer paging options soon. As I mentioned, a paging card is available for Palm Pilot models prior to the Palm III. Motorola has also announced plans to market a pager built into the Compact Flash form factor for use in Handheld PCs, Palm-size PCs, Auto PC products and other computers with a CompactFlash slot. No ship date or cost information is available as yet. Also, now that pagers have been reduced to a set of chips that computer vendors can build into their mobiles at a reasonable cost, expect additional PDAs and mobile computers to enter the market with onboard pagers.

Today, while paging coverage is better than anything else available, including analog cellular, I believe that the convenience of having a pager in a PC Companion or PDA is not sufficient to justify the expense of the service. Paging carriers do not have sufficient one-way paging capacity to be able to offer one price for standard paging devices and another, lower price for PC Companions. Until they figure out how to deliver more information for less money, I'm not sure how many PDA users will find the service compelling enough to continue using it beyond the first month or two.

The good news is that there will be some new paging options coming over the next six months or so. Some of these options will be priced lower than today's one-way offerings, and some will enable the PC Companion or PDA to respond to the network or to the person who sent the message. I'll review a few of these options in the next edition of Handheld PC Magazine.

  ABOUT THE AUTHOR

Andrew Seybold heads a computer and communications industry consulting and newsletter company, and publishes the well-respected Andrew Seybold's Outlook on Communications and Computing. He has an extensive radio communications and computer background, is recognized as one of the top analysts in these fields, and is a founder and President of the Portable Computing and Communications Association (PCCA). Andrew Seybold's Outlook can be reached at 408-338-7701, fax 408-338-7806, e-mail: lseybold@outlook.com