Am Do 10. Juli 2008 schrieb Joe Pfeiffer:
quoted text > Werner Almesberger writes:
> >Michael 'Mickey' Lauer wrote:
> >> I could be wrong, but IIRC FSO is powering the modem down if you shut =
it=20
down=20
quoted text > >> from console. gsm0710muxd is issuing AT@POFF once you SIGTERM it.
> >
> >That AT@POFF doesn't cut power to the modem. Instead, it tells the
> >modem to "power down", i.e., to enter its own standby mode, from
> >which it can be awakened by "pressing" the modem's "on" button.
> >(That "button" is in fact a transistor controlled by MODEM_ON line
> >which connect to the CPU's GPB7.)
> >
> >What does cut power to most of the GSM chipset is the GSM_ON line
> >which connects to the PMU's GPIO2.
> >
> >Alas, the modem's RF amplifier is not controlled by this (it doesn't
> >like anything to get between it and the battery), so the GSM
> >subsystem cannot be entirely cut off.
>=20
> I'm confused -- do you mean there is no way to turn off the modem's RF
> amp? What do other phones using it do to comply with airplane
> regulations?
>=20
>=20
The amp is supposed to be inactive by default, as long as no signal is comi=
ng=20
in to drive it. Think of it as an active audio box that's "always=20
on"(standby) and activates whenever a signal comes in.
Oscillators (transmitter) are forced powered down.
So there should be no issues here.
/j
