Glossary Section "R" ( Definitions )
RADSL Rate Adaptive Digital Subscriber Line
RAID Redundant Array of Independent Drives
RBOC Regional Bell Operating Company.
RBS Robbed Bit Signaling is used in T1 circuits. Instead of having a specific timeslot dedicated to provide signal (as is true with ISDN) , signaling bits for on-hook and off-hook are within the sixth, twelfth, eighteenth and twenty-fourth frames of each time slot. RBS is sometimes called CAS (Channel Associated Signaling) because it takes bits from the bearer channels for signaling.
RDI Remote Defect Indication
repeater A device which propagates electrical signals from one cable to another without making routing decisions or providing packet filtering. In OSI terminology, a repeater is a Physical Layer intermediate system.
RFC Request For Comments. The document series, begun in 1969, which describes the Internet suite of protocols and related experiments. Not all (in fact very few) RFCs describe Internet standards, but all Internet standards are written up as RFCs.
RJ11 A 4 position modular jack most commonly used for phone connections. The standard single line phone uses only 2 of the 4 wires.
RJ48C Registration Jack This is an 8 position modular jack commonly used for connecting to 1.544 Mpbs Digital Service.
rlogin A service offered by Berkeley UNIX which allows users of one machine to log into other UNIX systems (for which they are authorized) and interact as if their terminals were connected directly. Similar to Telnet.
robbed bit signaling ( RBS ) Robbed Bit Signaling is used in T1 circuits. Instead of having a specific timeslot dedicated to provide signal (as is true with ISDN) , signaling bits for on-hook and off-hook are within the sixth, twelfth, eighteenth and twenty-fourth frames of each time slot. RBS is sometimes called CAS (Channel Associated Signaling) because it takes bits from the bearer channels for signaling.
RoHS Restriction of the use of certain Hazardous Substances in electrical and electronic equipment in the EU (European Union) market. This Directive bans the placing on the EU market new electrical and electronic equipment containing more than agreed levels of lead, cadmium, mercury, hexavalent chromium, polybrominated biphenyl (PBB) and polybrominated diphenyl ether (PBDE) flame retardants.
ROI Return on investment
RS485 is a standard for half duplex data communications which is frequently used in multi-drop applications. Most commonly this is a 2-wire application. As many as 32 driver/receiver pairs can share a multidrop RS485 network. While many of the characteristics of RS485 are similar to RS422 the voltage range is greater.
RTMP Routing Table Maintenance Protocol
RTU Remote Terminal Unit
router A system responsible for making decisions about which of several paths network (or Internet) traffic will follow. To do this, it uses a routing protocol to gain information about the network and algorithms to choose the best route based on several criteria known as "routing metrics." In OSI terminology, a router is a Network Layer intermediate system. Historically, routers were called "gateways" in Internet terminology. See bridge, gateway, repeater.
routing metric The method by which a routing algorithm determines one route is better than another This information is stored in routing tables. Such tables include reliability, delay bandwidth, load, MTUs, communication costs, and hop count..
RPC Remote Procedure Call. A popular paradigm for implementing the client-server model of distributed computing. A request is sent to a remote system to execute a designated procedure, using arguments supplied, and the result returned to the caller. There are many variations and subtleties, resulting in a variety of different RPC protocols.
RS-232- An EIA-specified physical interface with associated electrical signaling between DCE and DTE. The most commonly employed interface between computer devices and modems. While this term is still used, it is more correctly an EIA-232-D.
RS-530 The physical connector use for RS530 is generally a DB25. This superseded the RS-449. The RS-530 is a balanced interface that was designed to replace the more expensive V.35 connector. RS-530 can operate to speeds of 2 Mpbs.
RSVP Resource Reservation Protocol. RSVP is a control protocol for use in multimedia applications to indicate to transmitting nodes the nature (such as bandwidth, jitter, or maximum burstiness) of the packet streams that they want to receive.
RTFM Read The Fantastic Manual. This acronym is often used when someone asks a simple or common question. The word "Fantastic" is usually replaced with a four letter variation and hand signals.
RTS - Request to Send is a signal sent by one modem to another advising that the modem is available and requesting that data be sent.
RTSC Read The Source Code.