Non-gprs Internet access options without wifi (cel-dialup)

Andreas Kostyrka andreas at
Sat Jan 13 14:57:34 CET 2007

* Rob <openmoko at> [070112 17:38]:
>    In the meantime, I was thinking about how I could get around the lack of
>    wifi last night and something occurred to me...  Would it be possible with
>    this phone to set up a PPP dialup server on my machine at home, and get
>    dialup access to the internet by calling my home number?  This would be a
>    lot cheaper than downloading via GPRS because Canadian wireless carriers
>    are all apparently run by a bunch of jerks.  Would any extra hardware (eg:
>    a modem) have to be built into the phone in order to get PPP dialup access
>    this way, or could it just be done through software?  If hardware is
>    needed, is it too late to consider adding it to the specs?

Yes it is possible, it's called CSD (circuit switched data).

The problem here is, that you will need to place "data" calls to a
landline, not "voice" calls. How these are billed depends upon your
network. Just doing a data call over a "voice" call is no really

Additionally, CSD connections range in the area of 9600-14400 bps
(depending upon error rate, etc.).

Having worked with this speed a year ago, because my DSL was broken, I
can certify that this makes for a quite different network experience
that what we are used nowadays.

There is a significant quality improvement going from CSD to HSCSD (HS
high speed) or GPRS. Both of these are things that are easily to
differate out by the operator, so you need to rely on their pricing :(

>    There any other non-obvious options for Internet access with this phone
>    that don't involve GPRS?  I suppose IP over Avian Carriers would work...

Well, you've got:
CSD (probably HSCSD)
Bluetooth (pan and potentially other profiles)
USB (needs external power injector, again, ethernet emulation or serial emulation with ppp on top)

The one open question is what one can get from MicroSD slot.

>    I apologize if this has come up on the list before, I didn't read every
>    message.
Well, there aren't that many messages.

Plus, please before claiming that data plans are unreasonable (they
are, but that's a different discussion) expensive, consider what you
might want to do with this:

*) hacking code (generic internet usage): small display, small cpu, no
keyboard. Not really.
*) Websurfing (http/https/(x)html/flash): only GPRS, really, you won't
be using it for stuff if it's not needed.
*) Email: Quite feasible with GPRS speeds, but doesn't need extreme
data amounts.
*) multimedia downloads (mp3): 3MB => minimum transfer time over 10
minutes. Basically with a 128kbps stream, gprs needs about 3 seconds
to fetch the data for one second realtime. Combined that you need a
MicroSD card anyway for storage of these, you will end up loading the
data via the card.

So basically, between the non-flat price structure, the speeds of GPRS
(which are at best POTS modem speeds), and the fact that you will be
doing mostly interactive stuff with a phone, one doesn't need that
many MBs.

E.g.: I've used a Sidekick and now use a Nokia 9500 intensivly, and I
seldom go over 1-2MB per day (despite it having EGPRS, which is a
qualitive jump).

OTOH, it's trivial to use up hundreds of MB with an UMTS data card
stuck in a laptop. But that's different usage, on a different hardware.


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