Hi Ashok,
An ATA would consume 2 - Essential licenses
License Types
License Type Descriptions
Enhanced This license type covers a user and the user’s primary phone when the system
classifies the primary phone as enhanced.
• The Cisco Unified IP Phone 6941 and Cisco Unified IP Phone 6961 use an
enhanced license if these phones are not set up as public space phones or
adjunct phones.
• The Cisco IP Communicator or Cisco Unified Client Services Framework use
this license type if it is the primary phone for the user.
• The Cisco Unified IP Phone 7937 uses this license type if it is the primary
phone for the user.
Basic This license type covers a user and the user’s primary phone when the system
characterizes the primary phone as basic. The Cisco Unified IP Phone 6921 and
Cisco Unified IP Phone 6911 use this license type if the basic license is available
and if the phone is not set up as an adjunct phone.
This basic license type allows a regular user (non-department user) to use
voicemail, Reach Me Anywhere, and Cisco Extension Mobility if the features are
enabled in the usage profile and supported on the phone model.
Essential This license type supports a user and the user’s phone when the system
characterizes the phone as essential. The Cisco Unified IP Phone 6901 and Cisco
VG224 Analog Voice Gateway fall into this category; for example, each analog port
on a Cisco VG224 Analog Voice Gateway consumes a unit in the license file.
Primary phones are not related to the analog/application only license type; that is,
each phone that is classified by the system as analog or application only uses one
license from this license type.
Adjunct Adjunct licenses are used for a secondary phone; that is, the user has a primary
phone assigned to him, and the user needs an additional phone. Adjunct licenses
apply to phones that are characterized by the system as of equal or lesser value than
the primary phone.
Voicemail This license type allows a regular user (non-department user) to use voicemail and
voicemail related features. A separate voicemail license is required for each regular
user (non-department user). For example, if you have 150 users that require
voicemail, you need 150 voicemail licenses.
http://www.cisco.com/en/US/docs/voice_ip_comm/cucmbe3k/8_6_1/system/01_license.html
Cheers!
Rob
