The services provided by professionals in particular field. For example, a company may charge a certain sum of money for the certain tasks their consultant accomplished for the company who ordered the service.
Cisco 6921 is inexpensive business class IP phone model supporting video connection (Cisco UC Phone 6921, Standard Handset).
Cisco 6921 IP phone supports up to 2 lines has full-duplex loudspeaker, supports call holding on each line, hold, transfer, conference keys, tricolor indication of line condition, functional keys for simplified use of IP phone functions.