RADSL: Rate-Adaptive Asymmetric Digital Subscriber Line
Rate-Adaptive Asymmetric Digital Subscriber Line (RADSL) is a variation of ADSL which automatically adjusts the connection speed depanding on the quality and length of the telephone line. In RADSL, the broadband modem is configured at startup to test the phone line and adjust the data rate. RADSL typically operates at a lower date rate than regular ADSL. Like ADSL, RADSL provides relatively more bandwidth for downloads and less for uploads.
Remote Alarm Indication (RAI), also known as yellow alarm signal, is a signal transmitted in the outgoing direction when a terminal determines that it has lost the incoming signal. Receiving remote alarm indication (RAI) means the far-end equipment over the T1 line has a problem with the signal it is receiving from the upstream equipment.
Rain Barrel Effect refers to signal distortion of a voice telephone line caused by the under attenuated echo on the return path. The resultant distortion gives a near-singing effect like that of speaking into a rain barrel.
Range Extender With Gain is a unit that provides a range extension in a loop for both signaling and transmission.
RBHC: Regional Bell Holding Company
Regional Bell Holding Company (RBHC), also known as Regional Bell Operating Companies (RBOC), refers to one of 7 regional companies created by the AT&T divestiture to assume ownership of the Bell operating companies. They are Ameritech, Bell Atlantic, Bell South, NYNEX, Pacific Telesis, Southwestern Bell and US West.
RBOC : Regional Bell Operating Companies
Regional Bell Operating Companies (RBOC) refers to those telephone carriers who were formed as a result of the breakup of AT&T and are based on a restructuring agreement that took effect in 1984. The RBOCs were organized into seven regional Bell holding companies called Ameritech, Bell Atlantic, Bell South, Nynex, Pacific Telesis, Southwestern Bell, and US West. Each RBOC was assigned a specific geographical area, and each geographical area was divided into service areas called LATAs (local access and transport areas). The RBOCs are also called the ILECs (incumbent local exchange carriers). In contrast, CAPs (Competitive Access Providers) and CLECs (competitive local exchange carriers) are companies that compete against the RBOCs in the local service areas. IXCs (interexchange carriers) are long-distance service providers such as AT&T, MCI, and Sprint. The Telecommunications Reform Act of 1996 changed the telecommunications landscape yet again. RBOCs were allowed to merge and the following mergers or acquisitions took place in the following years. The Act also attempted to increase competition by opening local markets. RBOCs were required to open their facilities to competitive providers and, if they complied according to the rules, were allowed to expand into long-distance markets.
Remote Defect Indication (RDI) is an indication in an ATM network that indicates a failure has occurred at the far end of the ATM network. The RDI alarm indication does not identify the specific circuit in a failure condition. When the physical layer detects loss of signal or cell synchronization, RDI cells are used to report a VPC/VCC failure. RDI cells are sent upstream by a VPC/VCC endpoint to notify the source VPC/VCC endpoint of the downstream failure.
Receive-After-Transmit Time Delay
Receive-after-transmit time delay refers to the time interval between (1) the instant of keying off the local transmitter to stop transmitting and (2) the instant the local receiver output has increased to 90% of its steady-state value in response to a fro signal from a distant transmitter.
Received noise power refers to the following different meanings: 1. The calculated or measured noise power, within the bandwidth being used, at the receive end of a circuit, channel, link, or system. 2. The absolute power of the noise measured or calculated at a receiving point. The related bandwidth and the noise weighting must also be specified. 3. The value of noise power, from all sources, measured at the line terminals of telephone set's receiver. Either flat weighting or some other specific amplitude-frequency characteristic or noise weighting characteristic must be associated with the measurement.
Receiver is a device on a transmission path which converts the signals as received from the transmission system into the signals required by the destination equipment.
Receiver Off-Hook Tone is one of the audible tones in telephone system, which is used to cause off-hook customers to replace the receiver on-hook on a permanent signal call and to signal a non-PBX off-hook line when ringing key is operated by a switchboard operator.
The Recorder Connected Tone is used to inform the customer that his/her call is connected to a recording machine and that he/she should proceed to leave a message, dictate, etc. It is to be distinguished from the recorder warning tone, which warns the customer that his/her 2-way conversation is being recorded. Recorder Warning Tone is a .5 second burst at 440 Hz every 5 seconds.
Recorder Warning Tone is one of the audible tones in the telephone system. When recording equipment is used, the Recorder Warning Tone is connected to the line to inform the distant party that the conversation is being recorded. The tone source is located within the recording equipment and cannot be controlled by the party applying the recording equipment to the line. This tone is required by law and is recorded along with the speech. Recorder Warning Tone is a .5 second burst at 1400 Hz every 15 seconds.
Redialer is an interface hardware device that interconnects between a fax device and a Public Switched Telephone Network (PSTN). A redialer forwards a dialed number to another destination. Redialers contain a database of referral telephone numbers. When the user dials a specific number, the redialer collects the dialed digits and matches them to a listing in its database. If there is a match, the redialer dials the referral number (transparent to the user) and forwards the call to the referral number.
Reed-Solomon codes are block-based error correcting codes with a wide range of applications in digital communications and storage. Reed-Solomon codes are used to correct errors in many systems including: (1) Storage devices (including tape, Compact Disk, DVD, barcodes, etc) (2) Wireless or mobile communications (including cellular telephones, microwave links, etc) (3) Satellite communications. (4) Digital television / DVB. (5) High-speed modems such as ADSL, cDSL, etc.
Reference circuit is a hypothetical electric circuit of specified equivalent length and configuration, having a defined transmission characteristic or characteristics, used primarily as a reference for measuring the performance of other, i.e. real, circuits or as a guide for planning and engineering of circuits and networks.
Reference noise in telecommunication is the magnitude of circuit noise chosen as a reference for measurement. Many different levels with a number of different weightings are in current use, and care must be taken to ensure that the proper parameters are stated.
Regeneration in telecommunication refers to the process of reshaping and amplifying received signals to their original form. This technique is usually applied to digital pulses.
Regenerative Repeater is a device which regenerates incoming digital signals and then retransmits these signals on an outgoing circuit.
Register, in telecommunication, is a part of an automatic switching system that receives and stores signals from a calling device or other sources for interpretation and action, some of which is carried out by the register itself.
Register Progressive Control refers to a generic type of switching system in which the call progresses blindly one step at a time through the network under control of a translator and a register into which the originating subscriber has dialed the desired telephone number.
Registered Endpoint, a concept in a VOIP netowrk, is an endpoint that has informed the Gatekeeper that it is online, active and ready to receive calls, and has received confirmation from the Gatekeeper of its registration request.
Relative Transmission Level is the ratio of the test-tone power at one point to the test-tone power at some other point in the system chosen as a reference point. The ratio is expressed in decibels. The transmission level at the transmitting switch board is frequently taken as a zero level reference point.
Relay refers to the following meanings: (1). A device, usually electromechanical, by which the variation in current in one circuit causes the opening or closing of contacts controlling the current flow in one or more other circuits. (2). A process of retransmitting signals or messages through an intermediate point or repeater.
Relay Logic refers to the equipment function in which algorithmic decision-making is performed by relay operations. The usual contrast is electronic logic in which the algorithm is carried out by two-state devices, such as flip-flops.
Release-guard refers to a message sent by an exchange in the backward direction after receiving a "forward-clear" message and when a circuit is placed in the idle condition.
Reorder Tone is a low tone indicating that the local or toll switching or transmission paths to the office or equipment serving the called customer is busy. This signal may indicate a condition such as a timed-out sender or unassigned code dialed. It is interpreted by either a customer or an operator as a reorder signal. Reorder on a local call is a low tone for 0.3 seconds on and 0.2 seconds off. Reorder on a toll call is a low tone for 0.2 seconds on and 0.3 seconds off.
Rerouting, in telecommunications, refers to the recommencement of route selection from the first point of routing control in the switching system routing process. It takes place when congestion is encountered at some intermediate switching point in the connection that is to be established.
Resistance Design is a design method for subscriber loop circuits design in a telecom service provider. The key point of this method is to employ wire with the smallest diameter (least amount of copper) to ensure a loop resistance less than the signaling limit of the central office equipment serving the loop.
Responsible Organization refers to, in telecommunications with 800 Portability, those organizations to whom the Number Administration Service Center (NASC) allows to make changes such as carrier, termination, 800 call routing (by time of day, location). A letter Of Agency (LOA) must be on file to change the Responsible Organization each customer/account.
Retrial refers to any subsequent attempt by a customer, operator, or a switching system to complete a call within a measurement period.
Return Loss refers to a measure of the dissimilarity of the impedance of a transmission line and the impedance at its termination. It is a ratio, expressed in decibels, of the power of the outgoing signal to the power of the signal reflected back from an impedance discontinuity. If the terminating impedance exactly matches the characteristic impedance of the line, there is no reflection and the return loss is finite.
Reverse Battery Supervision is a form of call supervision in which the signals are furnished from the terminating end of a loop to the originating office by reversing the direction of current flow.
Reverse Channel refers to the telecommunicating path in the dialing up network from the called party to the calling party. This is the opposite of a forward channel.
Reverting Tone is the same type of signal as a line busy tone. In No. 5 crossbar systems, a second dial tone is sometimes also used when a calling party identification digit is required. The Reverting Tone informs the calling subscriber that the called party is on the same line and that he/she should hang up while the line is being rung. Reverting Tone is Low Tone on and off every 0.5 second at -24 dBm0/frequency.
Ring refers to the following meanings in telecommunications 1. An audible signal. 2. The process of generating a signal to a subscriber's telephone set. 3. In a 3-conductor switchboard plug, the ring-shaped contact between the tip and the sleeve. 4. Ring topology in data networking.
Ring Conductor is one of two wires of a cable pair used in the subscriber loop that carries the battery power from the central office to the phone system at the customer premise.
Ring Tone refers to the audible signal generated in telephone system and sent to a subscriber's telephone set
Ring Trip is the process of removing the ringing signal from the line at the central office when the called station is taken off-hook.
Ringdown is a method of signaling which employs a ringing signal to operate a device such as a lamp in order to alert an operator. The term originates from the manual ringdown operation of a magneto telephone set.
Ringer is the device at a subscriber's telephone set which responds to a ring signal to produce an audible alert.
Rotary Dial Telephone is a (old) telephone set at which the dial signaling is entered from a rotary dial as opposed to a TouchTone dial.
Rotary Groups, also known as hunt group, refers to a series of telephone lines that are programmed to find the next “free line†when a call is received.
Route Advance refers to the routing within a telecom switching system to an alternate route trunk group (or trunk subgroup) when all trunks in a prior trunk group (or trunk subgroup) are busy.
Routing Alternate refers to the assignment of a substitute or an alternate path through a network for a call when the primary route is not available for immediate use.
Routing Code is the combination of characters or digits required internally by the routing process of a telecom switching system to route a transmission to the desired destination.
Routing Indicator is the address or routing code in the message header which indicates to the network as routing instructions for the transmission of the message to its final circuit or destination.
RS-232, a popular physical layer interface also known as EIA-232 or TIA-232, is a standard for serial binary data interconnection between a DTE (Data terminal equipment) and a DCE (Data communication equipment). It is commonly used in computer serial ports. A similar ITU-T standard is V.24.
RS-422, also known as EIA-422 or TIA-422, is the balanced electrical implementation of EIA/TIA-449 for high-speed data transmission. Now referred to collectively with RS-423 as EIA-530, it provides for data transmission, using balanced or differential signaling, with unidirectional/non-reversible, terminated or non-terminated transmission lines, point to point, or multi-drop.
RS-423, also known as EIA-423 or TIA-423, is the unbalanced electrical implementation of EIA/TIA-449 for EIA/TIA-232 compatibility.
RS-449, also known as EIA-449 or TIA-449, specifiecs the functional and mechanical characteristics of the interface between data terminal equipment and data communications equipment. The electrical signalling standards intended for use with RS 449 are RS-422 for balanced signals, and RS-423 for the unbalanced signals, with data rates up to 2,000,000 bits per second. The standard specified two D-subminiature connectors with 37 and 9 pins for the primary and secondary data circuits.
RS-530, also known as EIA-530 or TIA-530, is a balanced serial interface standard that generally uses a 25 pin connector. The specification defines the cable between the DTE and DCE devices. It is a replacement for EIA-449, which uses 37-pin connector. It is to be used in conjunction with EIA-422 and EIA-423.
Remote Switching System(RSS) refers to an electronic switching system that is remote from its host or control office. All or most of the central control equipment for the RSS is located in the host switching system.
RTP Redundancy is a method of overcoming packet loss by doubling packet payload without increasing the number of packets sent.
Request To Send (RTS) is the EIA/TIA-232 control signal that requests a data transmission on a communications line.