Subject: [NEXTEL-1] Scott D. Gardner Network Engineer- Air Force Communication Agency On Nextel (Dated)

From: Marcel <[email-masked]>
Date: Mon, 09 Dec 2002 05:02:46 -0500

Listen up: Sometimes, a phone’s just a phone

Your article, “Talk to me” [GCN, Aug. 20, Page 25] points out a common misconception among
public
safety users that a cellular, or in this case a hybrid, technology, namely a Nextel
Communications Inc.
phone, can replace land mobile radios (LMRs).

Cellular, personal communications and Nextel services all use large and sophisticated
infrastructures
to support their users. These infrastructures are subject to failure by cable cuts,
physical destruction
from earthquakes, storms or sabotage, and being overwhelmed by traffic because of an
event. These
factors limit their robustness during an emergency.

If you have tried to make a cellular call in the area of a major crisis, you may have
found you were
unable to complete the call. This is because all available circuits from that cell site
were used, and
because it couldn’t distinguish how important a particular user was, it wouldn’t grant
service.

Cellular companies, Sprint and Nextel are common carriers. In general they are prohibited
from
providing priority service to a specific group of users.

Would-be priority users of their services have the same rights as a single user who
happens to wander
into the same service footprint.

LMRs—those relatively big, walkie-talkies—operate on a dedicated system normally owned by
public
safety entities. They are not subject to being overwhelmed by non-public safety users.
They are more
resistant to failure during a crisis because they are built to support public safety users
and not to make
a profit.

Users can also use their two-way radios to talk directly to one another, for instance
inside a burning
building where common carrier service may not be available. Since LMRs are owned by public
safety
entities, their traffic can be encrypted. This gives them an edge over common carrier
systems, all of
which can be monitored.

Such radios also allow one user to talk to multiple users simultaneously. This is an
often-forgotten
advantage over common carriers, most of which are point-to-point systems. Nextel, a hybrid
LMR and
dispatch cellular system—it’s called an enhanced specialized mobile radio—does give you
one-to-several capability.

There is one other advantage to a land mobile radio. It allows you to instantly
communicate with your
dispatcher. A cellular or personal communications services call takes five seconds to
connect with
another user. Five seconds may not seem very long—unless you are being shot at, in a car
chase or
doing the things that public safety users do. The Nextel system will give you dispatch
capability, but
usually not as fast as a conventional or trunked public safety LMR system.

Scott D. Gardner
Network engineer
Air Force Communication Agency
Scott Air Force Base, Ill.

http://www.gcn.com/20_28/opinion/17079-1.html

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From: Rick Parrish <[email-masked]>
Date: Tue, 10 Dec 2002 03:25:36 -0600

Marcel wrote:

>Since LMRs are owned by public safety entities, their traffic can be encrypted. This gives them an edge over common carrier systems, all of which can be monitored.
>  
>
Oops - someone better tell Scott the news; like GSM is encrypted, iDEN 
could be (the carrier's decision), and PCS?? Commerical carriers have a 
greater need to encrypt their communications than most public safety 
organizations.

[ of course everyone here knows this ]

-rick