Grandstream Networks UCM6102 User Manual page 253

Enable Random Password
Disable Extension Range
Extension Ranges
Firmware Version 1.0.9.26
digits, with a minimum length of 4 digits. Repetitive digits pattern
(such as 0000, 1111, 1234, 2345, and etc), or common digits pattern
(such as 111222, 321321 and etc) are not allowed to be configured as
password.
2. Password for extension registration, web GUI admin login, LDAP and
LDAP sync requires alphanumeric characters containing at least two
categories of the following, with a minimum length of 4 characters.

Numeric digits

Lowercase alphabet characters

Uppercase alphabet characters

Special characters
If enabled, random password will be generated when the extension is
created. The default setting is "Yes". It is recommended to enable it for
security purpose.
If set to "Yes", users
pre-configured/configured on the UCM6100. The default setting is "No".
Note:
It is recommended to keep the system assignment to avoid inappropriate
usage and unnecessary issues.
The default extension range assignment is:

User Extensions: 1000-6299
User Extensions is referring to the extensions created under web
UI->PBX->Basic/Call Routes->Extensions page.

Pick Extensions: 4000-4999
This refers to the extensions that can be manually picked from end
device when being provisioned by the UCM6100. There are two
related options in zero config page->Auto Provision Settings, "Pick
Extension Segment" and "Enable Pick Extension". If "Enable Pick
Extension" under zero config settings is selected, the extension list
defined in "Pick Extension Segment" will be sent out to the device
after receiving the device's request. This "Pick Extension Segment"
should be a subset of the "Pick Extensions" range here. This feature
is for the GXP series phones that support selecting extension to be
provisioned via phone's LCD.

Auto Provision Extensions: 5000-6299
UCM6100 Series IP PBX User Manual
could disable the extension range
Page 252 of 305