Information Technology Reference
In-Depth Information
other group pickup
A method used with call pickup to answer a ringing phone from
another group number, which must be specified after pressing the GPickUp softkey.
overlay line
Allows shared line configurations by assigning multiple line instances to a sin-
gle physical line button (overlay) on a Cisco IP phone; configured by using the o, c, or x sepa-
rator.
packetization interval
The amount of data (typically audio) placed into each packet. Cisco
defaults to a 20 ms packetization interval for all codecs.
persistent chat
Group chats that are preserved when a user rejoins a chat room after log-
ging out.
phone user license
A license belonging to each Cisco IP Phone that allows it to communi-
cate with a Cisco Unified CME router or Cisco Unified Communications Manager server;
most newly purchased IP Phones come with a phone user license.
power failover (PFO)
The feature that allows the UC520 to complete calls out to the PSTN
from a designated analog phone in the event of a power failure.
private branch exchange (PBX)
A system that allows a company to run an internal, pri-
vate voice network; PBX systems are usually used in larger companies and provide unique
extensions to all devices.
private distribution lists
A collection of subscribers created by a single subscriber for
exclusive use by that subscriber.
Private Line Automatic Ringdown (PLAR)
A configuration used to enable “immediate
dial” applications, such as a phone that immediately dials an emergency number when a user
lifts the handset.
public distribution list
A collection of subscribers that is available to all Cisco Unity
Express subscribers to use as a distribution list.
pulse-amplitude modulation (PAM)
The process of sampling an analog waveform many
times to determine numeric electric amplitude values for digital conversion; PAM is typically
combined with pulse-code modulation (PCM).
pulse-code modulation (PCM)
The process of converting pulse-amplitude modulation
(PAM) values into binary number equivalents that voice equipment can transmit over digital
circuits.
pulse dialing
A type of address signaling in which the rotary-dial wheel of a phone con-
nects and disconnects the local loop circuit as it rotates around to signal specific digits.
Q.931
A signaling protocol used by ISDN CCS implementations.
quantization
The process of assigning analog signals a numeric value that can be transport-
ed over a digital network.
Real-Time Transport Control Protocol (RTCP)
The UDP-based protocol responsible for
transporting audio statistics; uses random, odd-numbered UDP ports from 16,384 to 32,767
for communication.
