future drop-in modems?

[Eric Olson-4]

Hi Everybody,
I follow gta02-core loosely, mostly just happy to read the updates :).
Anwyay, here's a modem idea that is hopefully feasible -- apologies if
you've discussed it already.

According to the openmoko-community list, there are 3G dongles such as
the huawei E169 3G USB dongle that work as a phone with the freerunner
and the asterisk software.  If such a thing works well as a phone, it
wouldn't be unreasonable to fabricate a phone without the modem, and
include a usb port/slot for the modem to be placed in afterwards.

This would allow more modularity, but would impose different size/layout
issues, and maybe a higher end-product cost.  Hopefully the cost would
drop eventually.

Anyway, glad to read the normal gta02-core updates.  Keep up the good work!

Eric

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[Flemming Richter]

On 2009-10-15, Eric Olson <[hidden email]> wrote:

> Hi Everybody,
> I follow gta02-core loosely, mostly just happy to read the updates :).
> Anwyay, here's a modem idea that is hopefully feasible -- apologies if
> you've discussed it already.
>
> According to the openmoko-community list, there are 3G dongles such as
> the huawei E169 3G USB dongle that work as a phone with the freerunner
> and the asterisk software.  If such a thing works well as a phone, it
> wouldn't be unreasonable to fabricate a phone without the modem, and
> include a usb port/slot for the modem to be placed in afterwards.
>
> This would allow more modularity, but would impose different size/layout
> issues, and maybe a higher end-product cost.  Hopefully the cost would
> drop eventually.

I think this would be nice if the USB modem could be
pushed into the case.

It would also let you detact the modem either to use it
in your laptop or to use the space where it was for a
USB flash drive.

Unfortunately, there is some downsides with this approach:
a) new case design would be required
b) those USB modems tend to be power hungry
c) it would make the rf design very hard (shielding)

>
> Anyway, glad to read the normal gta02-core updates.  Keep up the good work!
>
> Eric

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[Werner Almesberger]

Eric Olson wrote:
> According to the openmoko-community list, there are 3G dongles such as
> the huawei E169 3G USB dongle that work as a phone with the freerunner
> and the asterisk software.  If such a thing works well as a phone, it
> wouldn't be unreasonable to fabricate a phone without the modem, and
> include a usb port/slot for the modem to be placed in afterwards.

Hmm, how big is that beast ?

Cost seems to be difficult to determine, because these modems seem to
be sold generally with a contract. This can be good or bad.

What may be a problem with such an approach is RF access. The antenna
would almost certainly end up at a non-optimal place, unless one really
lets the modem protrude from the device. This could result in poor
connectivity, high power consumption, and problems with interference.

Power consumption during RF activity would almost certainly be an issue
as well, considering that the battery voltage would first have to be
boosted up to 5 V, and then dropped to whatever the modem uses
internally.

Not sure what to expect for standby power. USB has an efficient standby
mode, but I'm not sure if it's of much use for a 3G modem, with an
average current budget of only 2.5 mA over any 1 s interval. (Spikes
are allowed.)

- Werner

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