Octet. Eight (8) bits. Another term for a byte. However, a byte is not defined in all digital systems as 8 bits so the term 'octet' is used.

OFDM (Orthogonal Frequency Division Multiplexing). A technique that splits a wide frequency band into a number of narrow bands and inverse multiplexes data across sub-channels.

Offered traffic. The number of dialing attempts made to a subscriber within a specified time period.

Off-hook. A signal indicating that the telephone of the called party is engaged.

Off-line. A state used to identify that a device is not in operation.

OHG: Operators Harmonization Group. OHG is an industry body established to develop a single 3G cellular mobile standard.

ONAL (Off-network access line). A line connecting a telecommunications company network to the public network.

Off-network calling. Calling the public telephone system from within a private network.

OIW. A workshop for implementors of OSI. The North American regional forum at which OSI implementation agreements are decided.

OMUX (Output Multiplexer). A multiplexer at the output of a satellite transponder

On-hook. The status of telephone equipment that is ready to receive a call.

On-hook dialing. A method of dialing a telephone without the need to lift the receiver. The caller dials the number and uses the telephone speaker to listen to the status of the call. When the call is connected, the caller lifts the receiver and speaks.

On-network call. A call made within a private network.

One-way split. A facility that allows a telephone operator within a private exchange to speak to an extension without the caller hearing the conversation.

Online. The status of a device that is connected to another device and prepared to transmit or receive signals.

Online processing. The use of a computer/automated operator to operate equipment.

Open architecture. A network structure in which all hardware and software is based on industry standards in order to facilitate compatibility with as many other networks as possible.

Orbital period. The time that it takes a satellipe to complete one circumnavigation of its orbit.

Orbital Slot. The location of a satellite in orbit around the globe.

Origin Server. A server on which a given resource is located or created. It is often referred to as a web or HTTP server.

OSI (Open System Interconnection). A standard for a layered architecture that allows data to be transferred among systems through networks. See layer.

OSS (Operation and Support System). An application program that allows a network operator to monitor, analyze and control the telecommunications network.