OA&M: Operation, Administration and Maintenance
Operation, Administration and Maintenance (OA&M) is a group of management functions that provides system or network fault indication, performance monitoring, security management and diagnostic functions. Some systems require extensive end user provisioning functions, in this case, it is called Operation, Administration, Maintenance and Provisioning (OAM&P).
OADM: Optical Add-Drop Multiplexer
Optical Add-Drop Multiplexer (OADM) is an optical multiplexing device used in wavelength-division multiplexing (WDM) systems for mixing and routing different channels of light into or out of a single mode fiber. It has the capability of adding one or more new wavelength channels to an existing muli-wavelength WDM signal, or removing (dropping) one or more channels, routing those signals to another network path.
OAM&P: Operation, Administration, Maintenance and Provisioning
Operation, Administration, Maintenance and Provisioning (OAM&P) refers to a group of management funcions that provides system or network fault indication, performance monitoring, security management, diagnostic functions, configuration and user provisioning. Operations include coordinates actions between administration, maintenance, and provisioning. Administration includes designing the network, processing orders, assigning addresses, tracking usage, and accounting. Maintenance includes diagnosing and repairing problems that does not work as planned. Provisioning includes installing equipmet, setting parameters, verifying that the service is operational, updating, and de-installation.
Out-of-Band Control (OBC) refers to the standard method of issuing signaling commands on the special control channel, versus In-Band Control (IBC), on the in-band data channel.
Optical Carrier (OC) is a group of signal bandwidth in a SONET fiber optic network with many defined levels. It is typically denoted as OC-n, where n is the multiplexing factor of the basic rate of 51.8 Mbit/s. The current defined levels are:
OC-1 — 51.8 Mbit/s
OC-3 — 155.52 Mbit/s
OC-12 — 622.08 Mbit/s
OC-24 — 1.244 Gbit/s
OC-48 — 2.488 Gbit/s
OC-96 — 4.976 Gbit/s
OC-192 — 9.953 Gbit/s
OC-256 — about 13 Gbit/s
OC-384 — about 20 Gbit/s
OC-768 — about 40 Gbit/s
OC-1536 — about 80 Gbit/s
OC-3072 — about 160 Gbit/s
Optical Carrier One (OC1 or OC-1) is a SONET line with a transmission speed of 51.84 Mbit/s (payload: 50.112 Mbit/s; overhead: 1.728 Mbit/s) using optical fiber. OC-1 is the basic rate for the SONET optical fiber lines and the other rate levels of SONET are multipled based on the OC-1 speed. OC-1 is equivalent to STS-1 (Electrical level) and STM-0 (SDH).
Optical Carrier 12 (OC12 or OC-12) is a fiber optic network line with a SONET rate of 622.08 Mbit/s (payload: 601.344 Mbit/s; overhead: 20.736 Mbit/s) or 12 times the basic SONET signal transmitting rate of 51.84 Mbit/s (OC-1). OC-12 lines are commonly used by Service Providers as WAN connections. This connection speed is often used by mid-sized (below Tier 2) internet customers, such as web hosting companies or smaller ISPs buying service from larger ones. OC-12 is equivalent to STS-12 (Electrical level) and STM-4 (SDH).
Other Common Carrier (OCC) refers to telecommunications carriers in the US who were not part of the former original AT&T system.
Optical Carrier 192 (OC192 or OC-192) is a SONET rate of 9953.28 Mbit/s (payload: 9621.504 Mbit/s; overhead: 331.776 Mbit/s) over optic fiber lines, or 192 times the basic 51.84 Mbit/s SONET signal (OC-1). The WAN version of 10 Gigabit Ethernet is designed to interoperate with OC-192. As of 2006, OC-192 connections are the most common for use on the backbones of large ISPs. OC-192 is equivalent to STS-192 (Electrical level) and STM-64 (SDH).
Optical Carrier 3 (OC3 or OC-3) is a optic fiber line using SONET with a transmission speed of 155.52 Mbit/s (payload: 150.336 Mbit/s; overhead: 5.184 Mbit/s), or 3 times the basic 51.84 Mbit/s SONET signal (OC-1). OC-3 is equivalent to STS-3 (Electrical level)and STM-1 (SDH).
Optical Carrier 48 (OC48 or OC-48) is a fiber optic line with a SONET rate of 2488.32 Mbit/s (payload: 2405.376 Mbit/s; overhead: 82.944 Mbit/s) or 48 times the basic SONET signal transmitting at 51.84 Mbit/s. OC-48 connections are used as the backbones of many regional ISPs. OC-1 is equivalent to STS-48 (Electrical level) and STM-16 (SDH).
Optical Carrier 768 (OC768 or OC-768) is a fiber optic line with a SONET rate of 39,813.12 Mbit/s (payload: 38,486.016 Mbit/s; overhead: 1327.104 Mbit/s), or 768 times the basic SONET rate of 51.84 Mbit/s (OC-1). It's often referred to as "40 Gbit". OC-768 is equivalent to STS-768 (Electrical level) and STM-256 (SDH).
Optical Carrier 96 (OC96 or OC-96) is a fiber optic line with a SONET rate of 4976 Mbit/s, or 96 times the basic SONET rate of 51.84 Mbit/s (OC-1). It's not used much in the real world.
Other Common Carrier (OCC) refers to telecommunications carriers in the US who were not part of the former original AT&T system.
Optical Carrier Level n (OC-n) is a group of signal bandwidth in a SONET fiber optic network with many defined levels, where n is the multiplexing factor of the basic rate of 51.8 Mbit/s. The current defined levels are:
OC-1 — 51.8 Mbit/s
OC-3 — 155.52 Mbit/s
OC-12 — 622.08 Mbit/s
OC-24 — 1.244 Gbit/s
OC-48 — 2.488 Gbit/s
OC-96 — 4.976 Gbit/s
OC-192 — 9.953 Gbit/s
OC-256 — about 13 Gbit/s
OC-384 — about 20 Gbit/s
OC-768 — about 40 Gbit/s
OC-1536 — about 80 Gbit/s
OC-3072 — about 160 Gbit/s
Odd Parity, one of the parity processes, means that the total numbers of ones in the information data stream plus the parity bit (typically appended to the end of the data bitstream) is equal to an odd number of ones.
Offered Load is the total traffic load, including load that results from retries, submitted to a telecommunications system, group of servers, or the network over a circuit.
Offered Traffic is a measurement in telecommunications that stands for the total attempts to seize a group of servers.
Off-hook refers to the following meanings in telecommunications: (1) the signal that the telephone receiver has been lifted. Originating Off-hook activates a dial tone on switched networks. (2) the state of telephone that the receiver has been lifted.
Ones Density, also called pulse density, is a scheme that allows a CSU/DSU to recover the data clock reliably. The CSU/DSU derives the data clock from the data that passes through it. To recover the clock, the CSU/DSU hardware must receive at least one 1 bit value for every 8 bits of data that pass through it.
One-way Trunk is the trunk circuit that can be seized at only one end.
On-Hook is the normal inactive state of a telephone terminal. In this state, the switchhook contacts at the telephone instrument are open and no current signal is being sent to the central office.
ONI Order Tone is a tone with 700 Hz and 1100 Hz at -25 dBm0/frequency for .095 to 0.25 seconds that tells the ONI (Operator Number Identification) operator that a call has reached the position.
Only-route Trunk Group is a trunk group that is the one and only route for particular traffic items. It receives only first route traffic, does not receive overflow traffic, and has no alternate route.
Out-of-Service signaling(OOS) is a call signaling indicating that the network or phone station is out of service.
Originating Point Code (OPC) refers to numeric address in a SS7 network which uniquely identifies each signaling point. The OPC identifies the sending signaling point.
Open Wire is a transmission path consisting of a pair of wires, spaced a parallel distance apart and mounted on insulators, usually on a pole line.
OPSM: Operator Position Switching Module
Operator Position Switching Module(OPSM) refers to the operator services system for the AT&T 5ESS switch that gives phone companies and worldwide phone service administrators flexibility in deploying operators. The system is called the Operator Services Position System (OSPS), and its operation is based on the Integrated Services Digital Network (ISDN) capabilities of the 5ESS switch. These capabilities permit simultaneous data and voice communications between the switch and the operator's terminal equipment. OSPS allows the phone service providers to provide fully-featured North American and international operator service with operators located at a distance from the switching system.
Optical power budget refers to the allocation (in a fiber-optic communication link), of available optical power launched into a given fiber by a given source among various loss-producing mechanisms such as launch coupling loss, fiber attenuation, splice looses, and connector losses, in order to ensure the adequate signal strength at the receiver.
Optical power margin refers to the difference between (1) the optical power that is launched by a given transmitter into the fiber, less transmission losses from all causes, and (2) the minimum optical power that is required by the receiver for a specified level of performance. Optical power margin is usually expressed in dB. At ease, several dB of optical power margin should be included in the optical power budget.
Optical Receiver is a device in a optical transmission system that detects an optical signal, converts it to an electrical signal, and processes the electrical signal as required for a further use.
Optical Transmitter is a device that accepts an electrical signal as its input, processes this signal, and uses it to modulate opto-electronic device and produce optical signals.
Off Premise Extension (OPX) is an extension telephone, PBX station, or key system station located on property that is not contiguous with that on which the main telephone, PBX, or key system is located.
Order Tone is a high tone sent over interposition, local interoffice, or toll trunks. It indicates, 1) to the originating operator that the order should be passed; 2) to the receiving operator that an order is about to be passed. For Call Announcement and Automatic Display Call Indicator, the tone serves function two only.
Originating Resister is the equipment in a Number 5 Cross System that is connected to a subscriber initiating a call to receive the dial pulses or TOUCHTONE signals from the subscriber's telephone.
Originating User refers to the user who initiates a particular information transfer transaction. The originating user could be either the source user or the destination user.
Operator Service Call (OSC) refers to a call that is placed through a human operator or an automated operator.
Operation Support System (OSS) performs management, inventory, engineering, planning, and repair functions for telecommunications service providers and their networks. Operations Support Systems (OSSs), typically based on the Telecommunications Management Network (TMN) model, are designed to support telephone company staff members to automate their daily jobs such as order processing, line assignment, line testing and billing, etc.
OTM: Optivity Telephony Manager
Optivity Telephony Manager (OTM) is an application that provides single-point analysis, configuration, and management of Telephony networks using a Web browser or graphical user interface (GUI). The OTM suite, which is offered by Nortel Networks, is designed for the management of Meridian 1 and Communication Server 1000 systems.
Outbound, in telecommunication, refers to outward sending, call originating, or dialing Out.
Outgoing Calls Barred is a telecommunication facility that prevents a packet switch from accepting outgoing virtual calls from the data terminal equipment.
Outgoing Sender is an equipment in telecommunication network that transmits call completion information on an interoffice call.
Out-of-band signaling is a signaling technique using frequencies or channels outside the frequencies or channels normally used for information transfer. Out-of-band signaling often is used for error reporting in situations in which in-band signaling can be affected by whatever problems the network might be experiencing.
Outside Plant has different meanings depending on where it is used: (1) In civilian telecommunications, it refers to all cables, conduits, ducts, poles, towers, repeaters, repeater huts, and other equipment located between a demarcation point in a switching facility and a demarcation point in another switching facility or customer premises. (2) In DOD (Department Of Defense) communications, it is the portion of intrabase communications equipment between the main distribution frame and a user and instrument to terminal connection for a user instrument.
Out-Slot Signaling is a signaling scheme in that the signaling associated with a (voice or data) channel is sent over the same transmission path (channel) or circuit, but in a different time slot (s). An example of this scheme is the ITU-T 2.048 Mbps digital carrier system.
Out-WATS Line refers to telephone lines used only for outgoing calls. Out-WATS Lines are, in effect, fixed-rate long distance subscriptions.
Overfill refers to the condition in telecommunications that prevails when the numerical aperture or the beam diameter of an optical source, such as a laser, light-emitting diode, or optical fiber, exceeds that of the driven element, e.g., an optical fiber core. In optical communications testing, overfill in both numerical aperture and mean diameter is usually required.
Overflow Load refers to a part of the offered traffic of telecommunications that is not carried, i.e., overflow traffic equals offered traffic minus carried traffic.
Overhead information is the signaling information of directing or controlling the transfer of user information or the detection and correction of errors. Overhead information transferred across the functional interface between end users and a telecommunications system, or between functional units within a telecommunications system. Overhead information originated by the user is not considered to be system overhead information. On the other hand, overhead information generated within the communications system and not delivered to the user is system overhead information. Thus, the user throughput is reduced by both overheads while system throughput is reduced only by system overhead.
Overlap is a mode where call control is waiting for possible additional call information from the preceding PINX because it received acknowledgment that the subsequent PINX can receive additional call information.