On Thu, 2012-03-22 at 11:14 -0500, Dan Williams wrote: > On Sun, 2012-03-18 at 16:51 +0100, Aleksander Morgado wrote: > > Hoola, > > > > > I see that NM request signal quality from 3G modem. I need dbm or > > > similar. Any command line option while modem it is locked by NM. > > > I need obtain dbm or result of at+csq > > > > > > > You can query the signal quality retrieved by NM/MM directly using the > > DBus interface and the 'dbus-send' command line utility (assuming your > > modem is at index 0 here): > > > > dbus-send --system --dest=org.freedesktop.ModemManager --print-reply > > /org/freedesktop/ModemManager/Modems/0 > > org.freedesktop.ModemManager.Modem.Gsm.Network.GetSignalQuality > > > > That won't give you neither the raw dBm value nor the rssi, though. It > > will give you a computed percentage value [0,100] representing the > > signal quality. > > Right; most modems don't support reporting dBm or RSSI, including almost
That's 1/2 a lie, they support RSSI, which is the value they return from AT+CSQ. RSSI is an arbitrary unit that's assumed to be linear in scale (unlike dBm). CSQ is defined to be 0 - 31, and internally in NM that's normalized to a 0...100 scale. Technically GetSignalQuality *does* return RSSI, but may not be reported in the modem's native RSSI scale. On some devices (Ericsson MBM) the scale is 0...5 even. If you're looking for a much deeper RSSI, like radio diagnostic data, then that's actually impossible to get for most devices. Dan > all that only support AT commands. Proprietary interfaces like CnS, > QMI, WMC, or DIAG etc may support reporting dBm though. However, > remember that dBm is really only useful for 2G and 4G technologies. For > 3G, whether EVDO or UMTS, the unit you're really looking for is EC/IO > (energy-per-chip over interference) which is how signal quality is > calculated for [W]CDMA-based air interfaces. > > Dan > > _______________________________________________ > networkmanager-list mailing list > [email protected] > http://mail.gnome.org/mailman/listinfo/networkmanager-list _______________________________________________ networkmanager-list mailing list [email protected] http://mail.gnome.org/mailman/listinfo/networkmanager-list
