[RFI] Blackberry interference with conference room audio systems

[Mike Clarson]

Jim: You forgot the network where RIM placed their first Blackberries--the
RAM Mobile Data Network (on air since 1989) using the Mobitex format. This
later was renamed BellSouth then Cingular and has since been sold again.
Don't know the new name.--Mike, WV2ZOW

-----Original Message-----
From: rfi-bounces at contesting.com [mailto:rfi-bounces at contesting.com]On
Behalf Of Jim P
Sent: Monday, March 21, 2005 10:34 PM
To: Michael Germino; rfi at contesting.com; Leigh L Klotz, Jr.
Subject: Re: [RFI] Blackberry interference with conference room audio
systems


Leigh, I just want to be clear on this, as all people
may not have followed the 'evolution' and renaming
that GSM has gone through into it's current
manifestation - GPRS.

All this 'renaming' hasn't materially changed the
air-interface level of the underlying principle upon
which GPRS (General Packet Radio Service) is
based, and to a lesser extent, the next migratory
step, EDGE (Enhanced Data for Global Evolution).

These are based on _the same_ air-interface frame
structure, logic channel and 200kHz carrier bandwidth
and symbol rates as GSM (# bits/symbol changes in
EDGE for higher data rates, as does the modulation
format).

It's not until the last step towards "3G" cellular/data,
called (variously) UMTS and IMT-2000, that a major
change is made,and W-CDMA (Wide-CDMA) is used
for the air-interface (RF link).

Evolution of GSM to 3G/IMT-2000 via GPRS/ EDGE/ WCDMA
http://www.geekzone.co.nz/content.asp?contentid=2362

There are other 2-way wireless data networks out there
too, that actually predate today's GSM/GPRS/EDGE
networks; they were not as widely publicized as the big
cellular carriers have done in promoting their offerings ...

The original Blackberies, by RIM (Research In Motion)
actually used these other networks early on (and may
still yet to this day); networks such as Pagenet's ReFlex
R50 protocol, and PageMart's ReFlex R25 network - both
operating nationwide (originally designed for 2-way paging/
messaging, but adopted for PDAs as that fad -er-
technology matured).
.
Jim P  /  WB5WPA  /