Re: [NTLK] REPOST: Wireless

From: Dave Christensen (dc623_at_mac.com)
Date: Fri Nov 15 2002 - 11:23:33 EST


Doug Parker wrote:

>
>
>
> Okay, it probably wasn't anything I said ;-) but I never
> received any reply
> to this posting the first time, and I'm really curious how
> the wireless
> communication runs on the Newt. Here's the repost:
>
> --- begin ---
>
> Some ways to communicate using a Newt and PC cards:
>
> 1) by modem, via phone cord from the wall to the Newt

Unfortunatly the batteries are the weakest link in this
picture, but the faster transaction times of a 33.6 modem
can minimize this....

> 2) ethernet, via cat5 or whatever from the Newt to
> the RJ45 socket

Its great at work if you can get an extra port installed at
your desk, or if your spouse/significant other doesnt mind
the 50ft CAT5 cable strung around the house following you
into bed at night to read.

> 3) wireless ethernet, via 802.11 from the wireless
> card to a base station

This is sweet if I may say so, I only learned that my SMC
card was supported 6-8 weeks ago and havent had the need for
#2 since. I'm still using a dial-up gateway, but I can now
share it with all my devices without having to go back to
the home office and use CAT5. Battery life is the only
problem.... an hour or two at most.

> 4) cellular modem, via (?) (packet?)

Non-802.11 wireless connectivity breaks down into CSD and
Packetized data. CSD is circuit switched data, just like
using your modem at home, you dial out on a circuit that is
all yours for the call. When done with a cell phone (here in
the US), often all you pay is your standard minute bucket.
This is true for AMPS (2.4kbps-the holy grail of 9.6kbps,
expect more of the former then the latter, and you better
not be moving around as nobody seems to support MNP10 any
more), CDMA (9.6kbps to 14.4kbps, and you can move around)
which is a pseudo packetized medium as your data moves as
data in packets over a broadband cloud and is only modulated
for the PSTN at a modem gateway at your providers switch,
TDMA does not support CSD, GSM supports CSD similarly to
CDMA, however it is only 9.6kbps (in ver 1.0 systems), I
never tinkered with GSM data as Sprint/APC didnt have the
capability back in 1995-1997 when I had service with them.

N/AMPS, TDMA, CDMA and even GSM systems can provide CDPD
(Cellular Digital Packet Data), this 19.2kbps IP based
service is always on, you are authenticated through your
customer provided equipments serial numbers, it is relativly
encripted, and is quite robust (I used it for my primary ISP
for 14 months). CDPD can be overlayed on almost any 800mhz
system and supports roaming from one provider to another.
This is the only packetized data product on N/AMPS, and for
TDMA users. Next generation CDMA and GSM networks have
theoretical bandwidths of 144-256kbps, however in real life
people seem to be reporting 50-75kbps. Depending on the
vendor and their service plans, they may have a time metered
plan (where you are billed whenever you device is powered on
and connected to the cloud), usage based (you are charged
for each byte/kb/mb that is transmitted over the network,
but can leave your device connected indefinitly).
Additionally companies like Cingular (formerly BellSouth
Wireless Data, RAM mobile data) Mobitex and Ardis/Motient
provide 9.6k packet data services for the blackberry
devices. they used to provide packetized IP services but
have not heard much about them in the last 3 years. Either
Cinglular or Motient used to provide service for the
AllPoints card used in our beloved Newton's

> 5) others?

My brain is going to explode and even more people are going
to hit the delete key if I continue my diatribe on wireless
data.... :-)

> What do they call that type of always-on connection that
> Blueberry devices
> use to communicate?

Cingular for the 95X class, Ardis/Motient for the 85X class.

Cheers - Dave

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