AP-VP150 Video Phone Installation and Operation Manual, Edition 1.00
AddPac Technology Proprietary & Documentation
205 - 200
Connection
POTS
Stands for Plain Old Telephone Service. Reference: PSTN.
PPP
Stands for Point-to-Point Protocol. This protocol is the advanced version of SLIP that
enables a router-to-router connection or a host-to-network connection through
synchronous or asynchronous lines. SLIP is designed to be used on an IP, while PPP
is used along with network layer protocols such as IP, IPX, and ARA. PPP has a
bulletin board security mechanism such as CHAP and PAP. PPP has two sub-
protocols, LCP and NCP. Reference: CHAP, LCP, NCP, PAP, and SLIP
Protocol Stack
This is a collection of communication protocols that inter-work with one another and
that process communications in part or all of the seven layers of the OSI reference
model. All protocol stacks are not related to each layer of the OSI model, and one
protocol of a stack can process multiple layers at one time. TCP/IP is a typical
protocol stack.
PSTN
Stands for Public Switched Telephone Network. PSTN is a general term that refers to
various telephone networks and services used worldwide. PSTN is also called POTS.
PVC
Stands for either Permanent Virtual Circuit or Permanent Virtual Connection. PVC is
a virtual circuit installed permanently. PVC allows you to reduce a bandwidth for
setting up or releasing a circuit when a specific virtual circuit must always exist. As an
ATM term, PVC is called Permanent Virtual Connection.
Q.931 Signaling
This is an ITU standard that specifies ISDN signal processing methods. The H.225.0
standard uses a variation of Q.931 to set up or disconnect the session of H.323.
QoS
Stands for Quality of Service. QoS is the criterion of measuring the performance (e.g.
transmission quality and service availability) of a transmission system.
RAM
Stands for Random-Access Memory. RAM is a volatile memory that can be read or
written by a microprocessor.
RAS
RAS refers to a protocol for registration, connect acknowledgement, and status
protocol. RAS is used for H.323 to find or have a conversation with a gateway.
RISC
Stands for Reduced Instruction Set Computing.
Router
This is a network layer device that determines the optional route to which network
traffic is delivered by using one or more metrics. A router forwards packets from a
network to another network based on the network layer information. A router is
sometimes called a gateway. (A gateway in this meaning is getting older.) Compare
to: Gateway; Reference: Relay
RS-232
This is a frequently used physical layer interface, and is known as EIA/TIA-232
