Chapter 1 - Traditional Voice Versus Unified Voice Flashcards
Components of PSTN
Analog Telephone Local Loop CO Switch Trunk Private Switch Digital Telephone
Analog Signal
Method of signaling that uses properties of the transmission medium to convey sound characteristics
Loop Start Signaling
Method of signaling that relies on connecting the tip and ring wires connecting to a device to complete the electrical circuit
Ground Start Signaling
Method of signaling that relies on grounding wires connecting to a device to signal a new call
Glare
A user picks up and connects unexpectedly to an incoming call
Time-Division Multiplexing (TDM)
Method of transmitting multiple channels of voice or data over a single digital connection by sending data in specific time slots
Channel Associated Signaling (CAS)
Method of digital signaling in which signaling in which signaling information is transmitted using same bandwidth as voice
Common Channel Signaling (CCS)
Method of signaling in which information is transmitted using separate, dedicated signaling channel
Robbed Bit Signaling (RBS)
Implementation of CAS that steals the 8th bit of every 6th frame of a digital T1 circuit for signaling information
Q.931
signaling protocol used by ISDN CCS implementation
Local Loop
PSTN link between customer premises and telco
Private Branch Exchange (PBX)
System that allows a company to run an internal, private voice network. Used by larger companies
Key System
System that allows a company to run a private, internal voice network. Used by smaller companies
Signaling System 7 (SS7)
Protocol used within telephony service provider networks to provide inter-CO communication and call routing
E.164
International numbering plan created by the ITU & adopted for use on the PSTN
Quantization
Process of assigning analog signals a numeric value that can be transported over a digital network
Nyquist Theorem
Method of converting analog signals into digital format by sampling twice the highest frequency of the audio
Mean Opinion Score (MOS)
Subjective method of determining voice quality
G.722
Uncompressed, moderate complexity codec with much better voice quality than G.711 while still consuming the same 64-kbps of bandwidth (typically)
G.711
Uncompressed audio codec consuming 64-kbps of bandwidth
G.726
Compressed audio codec consuming 32-kbps of bandwidth
G.728
Compressed audio codec consuming 16-kbps of bandwidth
G.729
Compressed audio codec consuming 8-kbps of bandwidth
Real-Time Transport Protocol (RTP)
UDP-based protocol responsible for transporting audio packets. Uses random even numbered ports from 16,384 to 32,767 for communication
Real-Time Transport Control Protocol (RTCP)
UDP-based protocol responsible for transporting audio statistics; uses random, odd-numbered ports from 16,384 to 32,767 for communication
