Hi Ramzi,
BAT is a very nice method for adding large numbers of users (especially if you have the information in some format like excel or word already) so you can Copy/Paste. It is also very benign for a process like Adding users, this can be done during office hours without causing any issues. The best thing about BAT is that you can do some practice runs first to get used to the process and file requirements b4 going live. Try a few small trial runs with just yourself as the User that you are adding just to work out the kinks :) Have a look;
BAT - Adding Users
Adding Users
You can use BAT to add users to the Cisco CallManager database/Lightweight Directory Access Protocol (LDAP) Directory in batches, rather than individually.
BAT can also associate CTI ports to existing users. This ability proves useful if you are adding users who will have applications that require a CTI port, such as Cisco IP SoftPhone. See Adding Phones or CTI Ports, for more information.
To add users to the Cisco CallManager database/LDAP Directory in bulk, you must perform these steps:
1. Create a comma separated values (CSV) file to define individual values for each user or CTI port/user combination you want to add. We recommend you create the CSV file using the Excel file, BAT.xlt.
2. Use BAT to insert the CSV file to add the users to the Cisco CallManager database.
Creating the CSV File for Users
To add users to Cisco CallManager, you must create a CSV file. You can create a CVS file two ways. You can use the Microsoft Excel template called BAT.xlt or create the CSV using the sample text file. Each CSV file type, such as phones, phones and users combined, and so on, provides a sample text file. However, Cisco recommends that you use the BAT.xlt template because the data is validated automatically when you export to CSV format.
The BAT.xlt file provides data file templates with macros, support for multiple phone lines, and error checking, and exports the values into CSV files for phones, ***users, CTI ports, phone/user combinations, CTI port/user combinations, Cisco VG200 gateways, and FXS ports on Cisco Catalyst 6000 analog interface modules.
http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/bat/5_1_3/t04usrov.html
Hope this helps!
Rob
