change its CID mode while the driver is loaded, eg.
echo 0 > /sys/class/tty/ttyGU0/cidmode
-2.7. Unregistered Wireless Devices (M101/M105)
+2.7. Dialing Numbers
+ ---------------
+ The called party number provided by an application for dialing out must
+ be a public network number according to the local dialing plan, without
+ any dial prefix for getting an outside line.
+
+ Internal calls can be made by providing an internal extension number
+ prefixed with "**" (two asterisks) as the called party number. So to dial
+ eg. the first registered DECT handset, give "**11" as the called party
+ number. Dialing "***" (three asterisks) calls all extensions
+ simultaneously (global call).
+
+ This holds for both CAPI 2.0 and ISDN4Linux applications. Unimodem mode
+ does not support internal calls.
+
+2.8. Unregistered Wireless Devices (M101/M105)
-----------------------------------------
The main purpose of the ser_gigaset and usb_gigaset drivers is to allow
the M101 and M105 wireless devices to be used as ISDN devices for ISDN