hello
switch off your device , then switch it on again keeping down 147
on diplay you'll see SERVICE
now type 76200
set the flag corresponding to "metering mode"
switch handset off and then on
you'll see in the first line several numbers:
the first one is the signal strenght,
the second is the frequency used
the third is the timeslot and
the fourth ( in hex value) is the RPN
keep in mind that to switch off metering mode you have to enter in the service menu' and remove flag
and this procedure is valid for all gigaset professional series.