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panel
A part used to ensure proper airflow within a shelf and to ensure electromagnetic compatibility (EMC) by sealing up the slots of the shelf. It is an external part of a board and is vertically placed with the PCB. It includes the ejector lever, indicator, and port.
parts replacement
A maintenance operation of removing a faulty part or a part to be examined from a running device and then installing a new part.
password modification service
A service that allows a user to change the service password.
password-based call restriction
By using the service, a subscriber can prevent other subscribers from making outgoing calls on the phone of the subscriber. In addition, the subscriber can make outgoing calls by dialing the password.
patch
An independent software unit used for fixing the bugs in software.
PBX
pbx group line selection service
A service that allows the system to select a callee from the group according to the preset selection mode when an outer-group user calls the primary number of the PBX group.
PGND
Plain Old Telephone Service
The basic telephone service provided through the traditional cabling such as twisted pair cables.
point-to-point multimedia communication
The communication between two multimedia terminals. The media streams are exchanged without passing the core switching layer.
polarity reversal detection
A method used to realize immediate charging. Through the polarity reversal on lines A and B when a call starts and when the call ends, the charging terminal is informed of the start point and end point of charging.
policy on office direction selection
A policy of dynamically selecting an office direction from the office directions that the peer office belongs to as the routing from the local office to the peer office. The policy can be based on time, tariff, or circulation of office direction numbers in ascending order.
power distribution box
A power box installed at the top of the cabinet through which the power enters the cabinet and is re-distributed to various components, at the mean time, the Power Distribution Box protects the electric devices from current overload.
Power Distribution Frame
Power Distribution Frame. It is a high-current power supply in the equipment room.
power up
To start up a computer; to begin a cold boot procedure; to turn on the power
power-off survival
A feature that allows part of the analog phone users to make calls by connecting to the PSTN through analog trunks in the case that the device is powered off. This feature is available when there are analog trunks connecting the unified gateway device and the PSTN.
PRA
pra link
A type of common channel signaling link that usually occupy the 16th timeslot of an E1/T1 link. The PRA link uses the digital subscriber signaling No.1 (DSS1) signaling. The DSS1 signaling is a type of non-peer-to-peer user signaling. Before a PRA link is set up, the two ends of the link detect the network identifications (NIDs) of each other. The PRA link can be set up only when the NID of one end indicates the network side and the NID of the other end indicates the user side.
prefix
A method of summarizing a large number of addresses in a compact manner. The prefix, which would be at most the length of an address, specifies all addresses that start with the specific prefix.
PRI
Primary Rate Adaptation
An interface consisting of a single 64-kbps D channel plus 23 (T1) or 30 (E1) B channels for voice or data.
Primary Rate Interface
An interface consisting of 23 channel Bs and a 64 kbit/s channel D that uses the T1 line, or consisting of 30 channel Bs and a channel D that uses the E1 line.
Private Branch Exchange
Private Branch Exchange (PBX) is a customer premise switch used to connect customer telephones to LEC central office lines (trunks) as well as switch internal calls within the customers premises, usually with software-controlled features such as call forwarding and call pickup.
privilege user service
A service that allows a registered user to forcibly converse with a user that is already in a conversation.
protection ground
A grounding point on the metal surface of the cabinet and the devices in the cabinet. It ensures sound lightning proof, electricity shockproof, and disturbance proof capabilities of the equipment.
protection ground cable
A cable which connects the equipment and the protection ground bar. Usually, one half of the cable is yellow; while the other half is green.
protocol
A formal set of conventions and rules governing the formatting and sequencing of message exchange between two communicating systems.
PSTN
See public switched telephone network
public switched telephone network
Public Switched Telephone Network. A telecommunications network established to perform telephone services for the public subscribers.
Parent Topic: Glossary