RA (Rectifier Alarm) - The discrete lead designation used to report the failure of the start battery rectifier serving the engine/alternator unit. Can be taken directly from late model rectifiers or indirectly from an engine alarm cabinet. The alarm is sent from an engine alarm cabinet as a loop closure. The alarm is also included as part of the engine/alternator minor alarm (F & A).

Rack (Relay Rack) - A structure on which equipment is mounted.

RAIG (Resource Availability Information Group) - Contains information that is used to attach values of topology state parameters to nodes, links and reachable addresses.

RAM (Random Access Memory) - A chip or collection of chips where data can be entered, read and erased. RAM is the fastest memory device, but is volatile and will lose its contents when the power is turned off.

RBOC (Regional Bell Operating Company) - There are seven RBOCs, each of which own two or more BOCs (Bell Operating Companies).

RCC (Routing Control Channel) - VPI=0, VCI=18 is reserved as the VC used to exchange routing information between logical nodes. An RCC (Routing Control Channel) that is established between two Logical Group Nodes serves as the logical link information needed by LGNs to establish the RCC SVC between other nodes in the peer group and is derived from the existence of uplinks.< /P>

RD (Routing Domain) - A group of topologically contiguous systems which are running one instance of routing.

RDF (Rate Decrease Factor) - For ABR, controls the rate at which cell transmission decreases.

Reachable Address Prefix - A prefix on a 20-octet ATM address indicating that all addresses beginning with this prefix are reachable.

Real Time - A voice telephone conversation is conducted in real time; i.e. there is no perceived delay in the transmission of the voice message or in the response to it. In data processing or data communications, real time means the data is processed the moment it enters a computer, as opposed to batch processing, where the information enters the system and is stored to be processed at a later time.

Real Time Capacity - The capacity of the central computer processor of a stored program control telephone system to process the instructions coming in. 

Real-Time Clock - a clock that maintains the time of day, in contrast to a clock that is used to time the electrical pulses on a circuit.

Rectification - Conversion of alternating current into current flowing in only one direction (direct current).

Rectifier - Electrical apparatus or equipment that changes AC power to DC power.

Rectifier Paralleling - Operation of more than one rectifier on a parallel load-sharing basis.

Rectify - To convert alternating current into direct current.

Red Alarm - In T1, a red alarm is generated for a locally detected failure such as when a condition like OOF exists for 2.5 seconds, causing a CGA, (Carrier Group Alarm).

Redundancy - In a data transmission, the fragments of characters and bits that can be eliminated with no loss of information.

Redundancy of Chargers - The process of both quantifying and sizing of the chargers required to enable continuous system operation upon the failure of a single charger. (May not recharge batteries in allotted time, but will support the load.) (N+1 redundancy)

Redundant - (1) More than is actually needed for intelligibility; and (2) items of equipment which are provided in duplicate or triplicate so that a required grade of service may be reliably achieved. 

Registration - The address registration function is the mechanism by which Clients provide address information to the LAN Emulation Server.

Registration Number (FCC Part 68) - Approval number given to telephone equipment to certify that a particular device passes the tests defined in Part 68 of the FCC Rules. These tests certify that the phone won't cause any harm to the public network.

Registration Program - FCC program which governs the direct connection of terminal equipment, whether customer-provided or telephone company-provided, to the telecommunications network without the need for a protective connecting arrangement (PCA). An applicant for equipment registration is required to show the equipment meets technical standards developed by the FCC.

Regulated - (1) Controlled for uniformity; and (2) adhering to the rules of a government agency. Regulation: (1) Voltage regulation; (2) the regulation of levels over a transmission system; and (3) the control of sag of an open wire route.

Regulatory Groups - Local, state or federal entities that issue orders, findings, etc. which are binding upon providers and users of telecommunications and services.

Relay - An electro-mechanical device used to switch circuits. Consists of a coil which, when connected to a complete circuit, will create a magnetic field which will attract an armature to open or close contacts. 

Relaying - a function of a layer by means of which a layer entity receives data from a corresponding entity and transmits it to another corresponding entity.

Relay Rack Framework - Uniframe, ESS frame, unequal lange duct framework, and bulb type framework (floor supported) with equipment mounted on the side. Sheet metal enclosures are usually available for single bay applications where it is necessary to cover current carrying parts.

Reliability - A measure of how dependably a system performs.

Remote Access - Communication with a data processing facility through a data link.

Remote Alarm - Alarm indicating a fault condition at a distant central office.

Remotely Located Equipment - Any equipment associated with the telephone service, including terminals, etc., that is located remotely from the switch itself.

Remote Sensing - A means by which the power supply uses external "sensing" leads to monitor a stabilized output voltage and/or current at some point external to the power supply (usually at the batteries).

Repertory Dialing - Sometimes known as "memory dialing" or "speed-calling." A feature that allows you to recall from nine to 99 (or more) phone numbers from a phone's memory with the touch of just one, two or three buttons.

Reset - An action by which the power supply is brought back into operation after a malfunction has been corrected.

Resistance - Any electrical conductor will resist the flow of electrical current. As it resists the flow of current, the current becomes weaker. Resistance generates heat and occasionally light, and is measured in Ohms.

Resistance Grounded - Resistor inserted in grounding circuit to limit current.

Resistor - A device whose function is to put resistance into an electrical circuit.

Resistor Color Code - Colored markings on a resistor which indicate the value and tolerance.

Response Time - The time which elapses between the generation of an inquiry and the receipt of a reply. It includes transmission time, processing time, time for searching records and files to obtain relevant data, and transmission time back to the inquirer. In a data system, it is the elapsed time between the end of transmission of an inquiry message and the beginning of the receipt of a response message, measured at the inquiry originating station. 

Restricted Transit Node - A node that is to be used for transit by a call only in restricted circumstances. It is free from such restriction when it is used to originate or terminate a call.

RF (Radio Frequency) - Electromagnetic waves operating between 10 KHz and 3 MHz propagated without guide (wire or cable) in free space.

RFA (Rectifier Failure Alarm) - A discrete lead designated denoting the failure of a rectifier. Normally connected as a grounded make lead.

RFCs (Requests For Comment) - IETF documents suggesting protocols and policies of the Internet, inviting comments as to the quality and validity of those policies. These comments are collected and analyzed by the IETF in order to finalize Internet standards.

RFC1483 - Multiprotocol Encapsulation over ATM Adaptation Layer 5.

RFC1490 - Multiprotocol Interconnect over Frame Relay.

RFC1577 - Classical IP and ARP over ATM.

RFC1755 - ATM Signaling Support for IP over ATM.

RFI (Request For Information) - General notification of an intended purchase of equipment or equipment and lines sent to potential suppliers to determine interest and solicit general escriptive product materials, but not prices or a formal request.

RFI (Radio Frequency Interference) - the unintentional transmission of radio signals. Computer equipment and wiring can both generate and receive RFI.

RFP (Request For Proposal) - A detailed document prepared by a buyer defining his requirements for service and equipment sent to one or several vendors. A vendor's response to an RFP will typically be binding on the vendor, i.e. he will be obliged to deliver what he says in his RFP at the prices and following the conditions therein.

RFQ (Request For Quotation) - A document prepared by a buyer defining his needs for service and equipment in fairly broad terms and sent to one or several vendors.

RG (Ring Ground) - Use for the grounded output from a self-contained alarm system for power minor and ABSF audible paired with ±105V 20 cycle ringing. 

Ribbon Cable - Multi-wire cable that is flat instead of round in which conductors are laid side by side.

RIF (Rate Increase Factor) - For ABR, controls the rate at which cell transmission increases.

Ring - (1) As in Tip and Ring, one of the two wires needed to set up a telephone connection. (2) A reference to the ringing of the telephone set. (3) Design of a Local Area Network (LAN) in which the wiring loops from one workstation to another, forming a circle.

Ringback Tone - The sound you hear when you're calling someone else's phone. The tone you hear is generated by a device at your central office, and may bear no relationship to the sound the phone at the other end is (or is not) emitting.

Ring Bus (DC Plants) - A closed loop bus system of fused bus and battery feeder sections powered by paralleled rectifiers; an overall highly reliable DC power plant. The loss of a single section of the ring bus will not result in loss of power to the loads (service is not affected). Continuity of power is maintained until repair or replacement can be made.

Ringing - Alternating Current (AC) sent out from the central office along the local loop to the subscriber, typically 70 to 90 volts at 16 to 66 Hz (20 Hz is most widely used).

Ringing Generator - A device, either rotary or solid state, that generates voltage for ringing a telephone. Typically this voltage is 70 to 90 volts at 20 Hz.

Ringing Interval - In the U.S., ringing current is usually applied to a called line for one second, followed by three or four seconds of silence before another one second of ringing. In other countries, different periodicities are sometimes used.

Ringing Monitor - A device which continually monitors the ringing supply at a central office and gives an alarm if this fails or if the period of interruption becomes unacceptable.

Ringing Plant - Electrical apparatus or equipment that provides ringing power for subscribers' telephones, various tones (such as dial tone and busy tone), and interruption cadences as required by the type of office in which it is used.

Ringing Signal - Any AC or DC signal transmitted over a line or trunk for the purpose of activating a bell or other audible signaling device.

Ringing Tone - A low tone which is one second ON and three seconds OFF. It indicates that ringing current is being sent by the central office to the person receiving the call.

Ring Trans. (Ring Transfer) - A discrete lead designation signifying that the ring plant has transferred to the standby unit.

RIP (Routing Information Protocol) - a distance vector-based protocol that provides a measure of distance, or hops, from a transmitting workstation to a receiving workstation.

Ripple (Output) - A measurement of the RMS value of A Ccomponents superimposed on a DC source.

Ripple Voltage - The alternating component of the unidirectional voltage from a rectifier or generator used as a source of DC power.

RISC (Reduced Instruction Set Computer) - a generic name for CPUs that use a simpler instruction set than more traditional designs.

RM (Resource Management) - The management of critical network resources, such as bandwidth and buffers, at the node level. A value of 6 is reserved in the PTI (Payload Type Identifier) to indicate a RM cell.

RMON [version 1.1] (Remote Network Monitoring) is an extension of MIB-II that gives certain devices the ability to serve as micro-monitors for their segments of a network. RMON provides a means of distributing network monitoring functions down through the network to certain strategically placed smart devices (RMON probes).

RMON agents reside on network equipment much the same as typical SNMP agents, providing information to the collection points. Data from the collection points is stored until software interrogates the probe and displays the information for the network manager. The information is network and traffic-oriented in contrast to traditional SNMP information which is more device-oriented.

Information is gathered in groups such as statistics, history, alarms, hosts, and traffic matrix. RMON is typically used to get a ground-level view of traffic trends so appropriate scaling and growth plans can be made.

Roam - Using your cellular phone in a city besides the one in which you live.

Robbed-Bit Signaling - In T1, refers to the use of the least significant bit of every word of frames 6 and 12 (D4), or 6, 12, 18, and 24 (ESF) for signaling purposes.

ROM (Read Only Memory) - A memory device which is programmed at the factory and whose contents thereafter cannot be altered by a power breakdown or by being written to. 

Router - a device that forwards traffic between networks or subnetworks based on network layer information.

Route Server - A physical device that runs one or more network layer routing protocols, and which uses a route query protocol in order to provide network layer routing forwarding descriptions to clients.

Routing Computation - The process of applying a mathematical algorithm to a topology database to compute routes. There are many types of routing computations that may be used. The Djikstra algorithm is one particular example of a possible routing computation.

Routing Protocol - A general term indicating a protocol run between routers and/or route servers in order to exchange information used to allow computation of routes. The result of the routing computation will be one or more forwarding descriptions. 

RPQ (Request for Price Quotation) - Solicitation for pricing of a specific component, software product, service, or system.

RR (Relative Rate) - A feedback mechanism whose end result is to slow the transmission of cells down by some percentage (i.e., 50%) based on a congested condition.

RR (Round Robin) Queuing - Developed to allow Fair Queuing to be used with a large number of flows with a wide variation in bandwidth. It is very similar to Fair Queuing, as each flow is allocated its own dedicated queue and all queues are processed in some round-robin fashion.

RS-232-C (also RS-232) - A set of standards specifying various electrical and mechanical characteristics for interfaces between computers, terminals and modems. It consists of a 25-pin plug (male or female), each lead of which has a specific function such as timing, control, or the sending of data.

RSA (Rural Service Area) - The FCC designated 428 rural markets across the country and is still in the process of licensing cellular operators for them. See also MSA.

RTS (Request To Send) - an RS-232 modem interface signal (sent from the DTE to the modem on pin 4) which indicates that the DTE has data to transmit.

rtVBR (real time Variable Bit Rate) - One of the service types for transmitting traffic that depends on timing information and control and which is characterized by the average and peak cell rates. It is suitable for carrying traffic such as packetized (compressed) video and audio.