The system of Classes of Service (COS) helps defining rights for one or another extension in the PBX or Centrex systems. For example, few groups require more space for storing voice messages, while other need the redirection of calls to cell phones, the third does not have to make calls outside of the office network. With the help of this system one can change and configure settings.
Established in year 2000, C3Call Telecom Group hold licenses in Singapore, S Korea, Vietnam and Cambodia to provide telecommunications services to its partners. Today, we are interconnected to more than 100 telco partners worldwide.