All PCS services typically use the G.711 codec for RTP. This is essentially an uncompressed voice codec, which utilizes 80Kbps of bandwidth in each direction (upstream and downstream) on a customer network during an active call. While there is always some small amount of SIP traffic on the network that will be exchanged back and forth between phones or other devices at the customer location and the PCS servers, estimating the described below will help ensure that the ISP connection the customer intends to use to carry their voice services will be sized properly to effectively handle their VoIP traffic.
Example: Customer site will have up to 5 active calls at any given time
5 calls x 80Kbps in each direction = 400Kbps of upstream and downstream bandwidth required.
Bandwidth is consumed for all calls made from a SIP device through a system in the PCS cloud. The 80Kbps (in each direction) described above is per device involved in a call and represents the packetized audio sent and received.
Private Branch Exchange (PBX)
This is a system that automates the process of switching (or routing) calls to destinations within a business. All calls made to and from a company’s phones are processed by the PBX. For example, when you call a company’s main number, the call first goes to a PBX instead of directly to a desk phone. The PBX then forwards (or switches) the call to the correct desk phone within the company.
PBXs allow one 10-digit phone number to be shared among multiple in-house phones. They also provide a range of business telephony features such as centralized management of phones, extensions, and numbers; voicemail, auto attendant, call recording, call transfers, conference calls, activity reports, etc.
PBX systems operate by using either VoIP (Voice Over Internet Protocol) or via analog or digital phone lines. With a PBX phone system, the physical phone line coming into your business can be split into multiple lines, allowing you to support more telephones. Better yet, calls between users are free. Hosted PBX systems are recommended for businesses. The hosted PBX system is going to multiply the efficiency of the company once installed.
