[gta02-core] future drop-in modems?

Werner Almesberger werner at openmoko.org
Mon Oct 19 03:15:44 CEST 2009

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

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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