Easily add extension
Without having an available port at the PBX for internal extension, you can add IP Phone or Softphone through the network and it will will how to reach the IP Telephony Server.
Connect Remotely
Do you need to connect remote offices on the same telephony system? Do you need to keep send and receive calls through same telephony system even if you are outside the office or the country? Yes, it is possible with IP Telephony system.
Trunking
IP Telephony Systems can communicate with each other as one system using VoIP trunk. This can be applied between offices (locally or remotely), so it is another kind of scalability with high availability.
Increase Telephone Lines
Telephone lines need to be connected to the VoIP gateways at the telephone card. What if I need to increase my telephone lines capacity? Just add new telephone card or replace the one you have at your IP Telephony System.
Softphone
Without need to buy IP Phone (hardware) and without having network cable, it is possible to use softphone on the smart mobile phone or softphone on the computer.
Multiple Scenarios
Same Telephony System can handle different business scenarios for the same office: if your office is offering multiple services and each service has a known telephone number, so each telephone number can play different scenario.
Better Call Handling
Having the ability to route the calls from station to station or groups based on different statuses and using the voicemail with email notification are helping to avoid drop in calls which means better customer satisfaction.
Same Network
No need to have network for computers and network for telephones. The network cable will reach to one port at the IP Phone and another small network cable from another port of the IP Phone to the computer.
Recording & Reporting
For better quality and customer satisfaction, calls need to be recorded and reported. Easier and less cost with IP Telephony System.
Conferences & Others
IP Telephony Systems can communicate with each other as one system using VoIP trunk. This can be applied between offices (locally or remotely), so it is another kind of scalability with high availability.
Costly effective
Having all the PBX functions and having voicemail, after working hours and email notifications will be less cost in IP Telephony.