Multitech MultiVOIP 200, Руководство пользователя

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MultiVOIP 200 User Guide
Private Branch Exchange (PBX): A phone exchange located on the customer's premises. The PBX provides a circuit switching facility for
phone extension lines within the building, and access to the public phone network. See also "Exchange".
PROM (Programmable Read Only Memory - pronounced "prom"): A permanent memory chip that can be programmed or filled by the
customer after by the manufacturer has set initial values. Contrast with ROM.
Protocol: 1. A set of semantic and syntactic rules that determines the behavior of functional units in achieving communication. 2. In Open
Systems Interconnection architecture, a set of semantic and syntactic rules that determine the behavior of entities in the same layer in
performing communication functions. 3. In SNA, the meanings of and the sequencing rules for requests and responses used for managing the
network, transferring data, and synchronizing the states of network components. 4. Synonymous with line control discipline.
PSTN (Public Switched Telephone Network): A worldwide public voice phone network that is used as a telecommunications medium for
the transmission of voice, data and other information.
Public Data Network (PDN): A packet-switched network that is available to the public for individual ("subscriber") use. Typically, controlled
by a government or a national monopoly.
Public Switched Telephone Network (PSTN): The group of circuit-switching voice carriers, which are commonly used as analog data
communications services.
Pulse Code Modulation (PCM): 1. In data communication, variation of a digital signal to represent information; for example, by means of
pulse amplitude modulation (PAM), pulse duration modulation (PDM), or pulse position modulation (PPM). 2. Transmissions of analog
information in digital form through sampling and encoding the samples with a fixed number of bits.
Pulse dialing: One of two methods of dialing a phone, usually associated with rotary-dial phones. Compare with "tone dialing".
Q
Quantizing: The process of analog-to-digital conversion by assigning a range, from the contiguous analog values, to a discrete number.
R
Random Access Memory (RAM): A computer's primary workspace. All data must be stored in RAM (even for a short while), before
software can use the processor to manipulate the data. Before a PC can do anything useful it must move programs from disk to RAM. When
you turn it off, all information in RAM is lost.
Rate Enforcement: The concept in frame relay where frames sent faster than the CIR are to be carried only if the bandwidth is available,
otherwise they are to be discarded. (The frame relay network assumes that anything exceeding the CIR is of low priority.) Rate enforcement
makes sure that the network will not get so congested that it isn't able to meet the agreed on CIR
Recognized Private Operating Agency (RPOA): A corporation, private or government-controlled, that provides telecommunications
services. RPOAs, such as AT&T, participate as non-voting members in the CCITT.
Red Alarm: A T1 error condition generated when a local failure (e.g., loss of synchronization) exists for 2.5 seconds, causing a Carrier Group
Alarm (CGA). See also "Blue Alarm" and "Yellow Alarm".
Request for Comment (RFC): A set of papers in which Internet standards (published and proposed), along with generally-accepted ideas,
proposals, research results, etc. are published.
Ring Down Box: A device that emulates a CO by generating POTS calls for testing and product demos.
Ring Down Circuit: A tie line connecting phones where picking up one phone automatically rings another phone. A feature used for
emergencies to alert the person at the other phone of the incoming call.
RJ-11: An industry standard interface used for connecting a phone to a modular wall outlet; comes in 4-and 6-wire packages.
RJ-45: An 8-wire modular connector for voice and data circuits.
Robbed Bit Signaling: The popular T1 signaling mechanism where the A and B bits are sent by each side of the T1 termination and are
"buried" in the voice data of each voice channel in the T1 circuit. Since the bits are "robbed" infrequently, voice quality is remains relatively
uncompromised. See "bit robbing".
The robbed-bit signaling technique is used in D4 channel banks to convey signaling information. The eighth (least significant) bit of each of
the 24 8-bit time slots is "robbed" every sixth frame to convey voice-related signaling information such as on-hook, off-hook, etc., for each
channel.
Router: A device that connects two networks using the same networking protocol. It operates at the Network Layer (Layer 3) of the OSI
model for forwarding decisions.
Routing Information Protocol (RIP): A distance vector-based protocol that provides a measure of distance, or hops, from a transmitting
workstation to a receiving workstation.
RS232-C: An EIA standard for a serial interface between computers and peripheral devices (modem, mouse, etc.). It uses a 25-pin DB-25, or
a 9-pin DB-9 connector. The RS-232 standard defines the purposes, electrical characteristics and timing of the signals for each of the 25
lines.