| Term |
Definition |
| OAM |
Operation Administration and Maintenance Management framework defined by the ITU. OAM cells are special purpose ATM cells exchanged between two ATM entities for network fault and performance management, analysis and fault isolation. |
| OC |
Optical Carrier - A range of standards applying to optical communications. |
| OC-1 |
The optical interface designed to work with the STS-1 signaling rate in a synchronous optical network. |
| OC-3 |
Optical Carrier level-3 - A SONET channel that carries a bandwidth of 155.55 Mbps. |
| O-CDMA |
Optical code division multiple access. |
| OC-n |
The optical interface designed to work with the STS-n signaling rate in a synchronous optical network (SONET). n is a whole number integer between 1 and (currently) 48. |
| Octet |
A set of eight bits. |
| OCXO |
Oven Controlled Crystal Oscillator. |
| Odd Parity |
An error checking process whereby the transmitted characters have been forced, by the transmitter, to always have an odd numeric value. |
| OEM |
Original Equipment Manufacturer. |
| OFDM |
Orthogonal Frequency Division Modulation. |
| Off-hook |
The state which defines that a telephone circuit is available for use. |
| Office Class |
The definition of a telephony switching/routing facility within the transmission hierarchy. |
| Off-load |
The process whereby network overheads are removed from a specific node. |
| Ohm |
The electrical unit of resistance. The value of resistance through which a potential of one volt will maintain a current of one ampere. |
| On Hook |
The normal, inactive, condition of a telephone system terminal device. |
| One Way Trunk |
A line between a PBX and a Central Office or between Central Offices where communication proceeds in one direction only. |
| OP AMP |
Operational Amplifier. |
| OPC |
Organic Photo Conductor. |
| Open Air Transmission |
The type of transmission which does not require a "closed" (wire, fiber, etc.) transmission. May also be referred to as non-contained transmission. |
| Optical Cavity |
A region bounded by two or more mirrors or other reflecting surfaces which are aligned so to provide multiple reflections. An example of an optical cavity would include the resonator in a laser. |
| Optical Channel Spacing |
The wavelength separation between adjacent WDM channels. |
| Optical Fiber |
Any glass or plastic fiber that is manufacture for the transmission of light signals. |
| Optical Fiber Amplifier |
A device that amplifies an optical signal directly, without the need to convert it to an electrical signal, amplify it electrically, and reconvert is to an optical signal. |
| Optical Polarization |
The term used to describe the orientation in space of time varying field vector of an optical signal. |
| Optical Time Domain Reflectometry |
A method for evaluating optical fiber based on detecting and measuring backscattered (reflected) light. Used to measure fiber length and attenuation, evaluate splice and connector joints, locate faults, and certify cabling systems. |
| Optical Transmitter |
This is an optoelectronic circuit that converts an electronic signal into an optical signal, the later bearing the same intelligence as the earlier. |
| OSCAR |
Orbiting Satellite Carrying Amateur Radio. |
| Outgoing Access |
A CCITT description of the ability of a device in one network to communicate with a device in another network. |
| Out-of-Band Signaling |
A method of signaling that uses the same path as voice-frequency transmission, but in which the signaling band is outside the band used for voice frequencies. |
| Overscan |
When an image is displayed, it is "overscanned" if a small portion of the image extends beyond the edges of the screen. Overscan is common in TVs that use CRTs to allow for aging and variations in components, temperature and power supply. |
