Interphase Tech iSPAN User Manual download pdf (Page 226)

206 Interphase Corporation

PMC (PCI Mezzanine Card) ◆ A daughter-card form factor imple-

mentation of the PCI bus specification.

POTS (Plain Old Telephone Service) ◆ Conventional voice grade

service and cabling infrastructure.

PPP (Point-to-Point Protocol) ◆ A dial-up protocol that allows a

computer to use TCP/IP networking to connect remote access devices,

such as modems, to the Internet or other TCP/IP based networks.

PPP/MP (Point-to-Point Protocol/Multilink Protocol) ◆ See Multi-

link PPP.

PRI (Primary Rate Interface) ◆ A type of ISDN service that offers 23

B-channels at 64 Kbps and one D-channel at 64 Kbps (23B+D). In

Europe, PRI provides for 30 B-channels and two D-channels

(30B+1D).

Private Line ◆ Synonym for a leased line. Dial voice line that does

not terminate at the voice private automatic branch exchange or that

does not appear on other sets in a key system.

Protocols ◆ A set of rules that define how different computer sys-

tems and other devices interoperate with each other.

PSTN ◆ Public Switched Telephone Network.

PVC (Permanent Virtual Circuit) ◆ A logical link whose endpoints

and class of service are defined by network management.

For Frame Relay, analogous to an X.25 permanent virtual circuit, a

PVC consists of the originating frame relay network element address,

originating data link control identifier, terminating frame relay net-

work element address, and termination data link control identifier.

Originating refers to the access interface from which the PVC is initi-

ated. Terminating refers to the access interface at which the PVC stops.

Many data network customers require a PVC between two points.

QLLC (Qualified Logical Link Control) ◆ An X.25 protocol that

allows the transfer of data link control information between two

adjoining SNA nodes that are connected through an X.25 packet-

switching data network. The QLLC provides the qualifier Q bit in X.25

data packets to identify packets that carry logical link protocol infor-

mation.

Q.921 ◆ This is the link layer protocol for ISDN.

Q.931 ◆ This is the network layer protocol for ISDN. Q.931 was

developed for out-of-band call control.

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Interphase Tech iSPAN User Manual Page 226