Motorola Series M - Manual (Page 53)

Using the Options Menu 51 English
Phone Setup Menu
Select Phone Line
This option allows you to switch between Line 1 and Line 2.
AAvailability depends on the type and settings of the SIM
card, and/or your subscription to this feature.
Adjust Ring Volume
This option is used to set the incoming call ring tone volume.
The volume will be displayed as follows:
\ Press to adjust the earpiece speaker volume. Release the key
and hold it down again to change direction.
Ringer On or Off
Sets incoming call alert to either a ringer tone or a display
message.