A phone call begins at the subscriber loop, travels to the central office, and then to the PSTN where the Signaling System No. 7 control system sets up, tears down, and routes calls between nodes.
- [Instructor] A softphone is an application…on a computer with a phone interface…that uses voiceover IP to make a call.…Prior to softphones, we used a standard telephone…to make a call.…A hard line has a microphone and a speaker,…a ringer, a hook, and a dial switch.…A battery powers the telephone…and a line card has many functions that includes signaling,…line supervision and termination.…
In a standard telephone, two wires make up…the loop that enables signaling.…On-hook means the switch is open.…Wire are not connected and there is no electricity flowing.…Off-hook means the switch is closed.…Wires are connected and there is electricity flowing.…To make a call, the user picks up the handset…and dials a number.…The signal travels to the receiver which initiates ringing.…
A phone call begins at the subscriber or local loop…which carries the signal from the subscriber's home…to the central office over a copper cable.…The signal then goes to the public switch…telephone network to SS7 and then on to internet.…The final path will depend on the destination…
Lisa Bock compares the traditional Public Switched Telephone Network (PSTN) to VoIP, and discusses the framework and components necessary for VoIP to be possible. She reviews codecs, including characteristics such as bitrate and voice quality; protocols for setup, communication control, and data transport; and media gateways, signaling protocols, and intermediary systems such as translators and mixers. Lisa then reviews business integration and the importance of conducting a needs analysis and network assessment prior to implementation. Learn about the many value-added services UC can provide, such as integrating VoIP with email, billing, management software, and other customer management systems. Lisa wraps up with a discussion on how ensuring quality of service (QoS) in a VoIP network minimizes latency and jitter and the importance of VoIP security to prevent malware, impersonation, hijacking, and denial of service attacks.
- History and evolution of PSTN
- UC overview and components
- Gateways, including signaling gateways, translators, and mixers
- Integrating VoIP and UC into your business network