Wireless modem WITHOUT Internet

I have a Windows CE handheld application for which I need a wireless
modem. First off, the handheld itself doesn't have cellular phone
capability, so any modem would have to be external.

Right now, remote handhelds connect to the back-end system through a
dial-up PPP connection to the customer site, NOT to the Internet (for
security reasons, almost nothing is exposed to the Internet, and even
VPN connections are verboten without orders signed in triplicate, sent
in, sent back, queried, lost, found, subjected to public enquiry, lost
again, and finally buried in soft peat for three months and recycled
as firelighters).

The modem the handheld uses is embedded in the charging cradle, so
this is a pretty straightforward process:

Handheld -> Modem -> Phone line -> Modem -> Host

We would now like to send data in a more timely fashion, namely two or
three times a day while the driver is out taking orders. Again,
connecting to the host via the Internet is NOT possible.

Pretty much everything advertised as a cellular modem these days is
not a modem as we knew them five years ago but rather is a bridge to
the data network of the cellular service provider.

What I'm looking for is a cellular modem that can run on a GSRM or
EVDO network, one that will happily call and talk to a regular modem
sitting on a regular phone line at the other end. Ideally, the
handheld should be able to talk to the modem via Bluetooth, but a
serial connection would also be acceptable. I would also like the
option to mount the modem in the truck, so a 12V power input would be
very helpful. Can anyone point me to a product that might suit?

Kevin Dean schrieb:
> [...]
> What I'm looking for is a cellular modem that can run on a GSRM or
> EVDO network, one that will happily call and talk to a regular modem
> sitting on a regular phone line at the other end. Ideally, the
> handheld should be able to talk to the modem via Bluetooth, but a
> serial connection would also be acceptable. I would also like the
> option to mount the modem in the truck, so a 12V power input would be
> very helpful. Can anyone point me to a product that might suit?

In the GSM world, what you are looking for is a device and a network
that support CSD or better yet HSCSD, (high speed) circuit switched data.

This method of data transfer has become quite uncommon, and apparently
the operators no longer maket it actively. However, most GSM networks
and many phones still support it. I guess you will need to talk to the
support people of your network to find out if they still have (HS)CSD
and if they can offer you a device that works with it.

Andreas

At 02 Oct 2007 19:05:28 +0000 Kevin Dean wrote:

> Pretty much everything advertised as a cellular modem these days is
> not a modem as we knew them five years ago but rather is a bridge to
> the data network of the cellular service provider.


Correct. These are likte llular equivalents of "broadband" cable/DSL
modems.

> What I'm looking for is a cellular modem that can run on a GSRM or
> EVDO network, one that will happily call and talk to a regular modem
> sitting on a regular phone line at the other end.

Frankly it just doesn't exist- GPRS and EVDO are direct-to-internet
connections.

> Ideally, the
> handheld should be able to talk to the modem via Bluetooth, but a
> serial connection would also be acceptable. I would also like the
> option to mount the modem in the truck, so a 12V power input would
be
> very helpful. Can anyone point me to a product that might suit?


Believe it or not, the "modem" you're looking for is simply a
bluetooth cellphone. To do PPP, you'll need a provider that still
offers dial-up ("1G") data connections. (NO cellphone or GSM modem
is a "real" modem in the traditional sense- analog modem tones don't
survive the compression/decompression and latency of a digital
cellular call. Instead, the "modems" exchange packets with the
carrier via "Circuit Switched Data" or CSD, and the carrier routes it
to a bank of "real modems" at their HQ to connect with the outside
world.) T-Mobile in the US still allows CSD, but for how long is
anyone's guess. It's used very rarely these days, due to the
"blazing" 9600-14,400 bps speed. The other major carriers used to
offer it as well, so you'll have to check if they still do. (The
hardest part is getting them to understand what you want. It might
help to just tell them you need to send/receive faxes over the
cellphone- the same account feature that allows faxing allows dial-up
modem access.)

No American prepaid cellular service allows CSD, so it'll have to be
a monthly plan- be careful while testing for suitability and check
the "grace period" each carrier you try gives you to cancel before
you get locked into a contract.


Good luck!


--

"I don't need my cell phone to play video games or take pictures
or double as a Walkie-Talkie; I just need it to work. Thanks for
all the bells and whistles, but I could communicate better with
ACTUAL bells and whistles." -Bill Maher 9/25/2003

Thank you to Andreas Wenzel and Todd Allcock, those are the answers I
was looking for. I've packaged up what you've told me about CSD,
along with what I was able to find on my provider's (Bell Mobility's)
web site, and sent it off to our account manager at Bell Mobility to
determine if the feature is still available and if so what the long
term plans are.

Kevin Dean <Kevin.Dean@datadevelopment.com> wrote in
news:1191351928.914859.122270@w3g2000hsg.googlegroups.com:

> I have a Windows CE handheld application for which I need a
wireless
> modem. First off, the handheld itself doesn't have cellular
phone
> capability, so any modem would have to be external.
>
>

Kevin, can you port your application to a small Linux box like
the Nokia N800?
http://www.nseries.com/products/n800/#l=products,n800
I alerted because I'm waiting for my new N800 to be delivered.

It has a full, unhobbled-by-Sellular-Phone-Company, Bluetooth
modem capability you can connect it through many Bluetooth
Sellphones back to your secure server with no internet
connection. Turn off its wifi to prevent logons through wifi
internet links and it will be very secure on Bluetooth. Being
Bluetooth-connected in a separate box also eliminates Sellphone
company "upgrades" turning off its functions via those secret
backdoors Sellphones all have installed in them.

Being a Linux box, open sourced as it is, you're not hobbled
porting your applications to it, either! This opens your window
into the fine OS like the thousands of hackers who have adopted
it across the planet. You may even find it more convenient, and
far more practical, to web browser base your application on the
server rather than the units. N800 comes with Linux Opera with
FLASH, full plugin capability, multimedia capability, etc., most
handhelds either don't properly support or have disabled by the
Sellphone carriers trying to force users to buy access to from
them. The Linux box bypasses this nonsense.

You could have them dialin to the secure server via Bluetooth to
a Bluetooth phone modem over Sellular, then connect to an
encrypted webpage your application doesn't support, I'd bet, for
real over-the-air security, not just hoping noone is listening.
Skype, for instance, is so encrypted to prevent snooping and it
has a new Linux version just for this phone's OS. The phone
supports TWO 8GB SD cards and has internal memory for your
application storage. Being able to simply move the card-based
database to the office PC for synchronizing also increases your
security, not having to transmit the syncing data over the air.
Of course, that's also lots faster moving the big cards,
directly...

Check it out. I'm anxiously waiting mine for a different
purpose, having a pocketable Skype phone I can connect to free
webpage-based wifi hotspots I have to carry a laptop to connect
to, now. That and having a REAL browser on REAL bandwidth makes
it for me a very useful internet device.



Larry
--
Please - Turn OFF cruise control when
you turn on windshield wipers!