Hi Bongani,

You definately require DLU Licenses to run the IP Phones :)

Seats is related to the Number of Users. DLU's is related to the number, in total, of Devices x DLU/per Device. In CCM 5.x and above IP Phones require DLU's or Device License Units that must be purchased from Cisco;

Device licenses are required for Cisco devices and for third-party devices,with the flexibility to replace third-party devices with Cisco devices. Device licenses are sold in increments of device-license units (DLU's). Device-license units are assigned to each device connected to Cisco Unified CallManager 5.0. Each device is assigned a unit number based on the type and capabilities of the device. Devices with more complex and high-end capabilities are assigned a higher number of units compared to devices with basic capabilities,

From this good Q & A doc;

http://www.cisco.com/en/US/products/sw/voicesw/ps556/products_qanda_item0900aecd805009fc.shtml

Licensing

Application and phone software licenses are enforced. The system manages the maximum number of devices that can be provisioned.

• Each device (Cisco Unified IP phones, third-party devices, and video devices) provisioned in the system corresponds to a number of device license units (DLUs), depending on its capabilities; the total number of units is managed in Cisco Unified CallManager to determine capacity.

• DLUs must be purchased to cover the number of devices connected to Cisco Unified CallManager.

• Third-party SIP devices require DLUs for operation with Cisco Unified CallManager.

Here is the DLU breakdown;

Cisco Unified IP Phone 7902G = 1

Cisco Unified IP Phone 7905G = 2

Cisco Unified IP Phone 7911G = 3

Cisco Unified IP Phone 7912G = 3

Cisco Unified Wireless IP Phone 7920 (no battery) = 4

Cisco Unified IP Conference Station 7936 = 3

Cisco Unified IP Phone 7940G = 4

Cisco Unified IP Phone 7941G = 4

Cisco Unified IP Phone 7941G-GE = 4

Cisco Unified IP Phone 7960G = 4

Cisco Unified IP Phone 7961G = 4

Cisco Unified IP Phone 7961G-GE = 4

Cisco Unified IP Phone 7970G = 5

Cisco Unified IP Phone 7971G = 5

Cisco Unified IP Phone 7985G = 6

Third-party SIP device (basic) = 3 (third-party)

Third-party SIP device (advanced) = 6 (third-party

http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/admin/5_0_1/ccmsys/a02licen.html

Here is the DLU Calculator;

http://ciscoknowledgenetwork.com/uc/documents/cm_device_calculator.xls

Hope this helps!

Rob