XM Satellite Radio P/N 08A15-1E1-000 - Manual (Page 5)

5
Sound in your car
The signal is broadcast in a digital format so that if you do run into a
situation where both the satellite antenna and the ground-based
antenna lose the signal the sound will drop off completely. This
condition would result in no static and may sound as though the unit
were shut off. As soon as the obstruction is cleared or a ground-
based signal is re-established the sound will come back on. If you
do experience a loss of signal, check the display module to make
sure it is powered on and check the display for NO SIGNAL. Refer
to page 15 of this manual for a display of messages.