V10: Identities - Login Information(Section): Display number for idle screen
<user_idle_number idx="INDEX" perm="PERMISSIONFLAG">VALIDVALUE</user_idle_number>
This setting only works on the phones with the color menu and version 10. If you enter a name or number in this ﬁeld, the entered value replaces the account number / identity shown in the subtext of the idle screen for this particular identity. This information is not sent out to anyone, but is merely shown on the phone’s display for your information.
Starting with V. 10.1.31.0 this setting will also be applied to the call screens if set.
e.g. 123, provider-abc, my extension: 123, Company A, +49 30 398 33 123