Glossary

(1) A complete electrical circuit. (2) The pair of wires that winds its way from the central office to the telephone set or system at the customer

A type of diagnostic test in which a transmitted signal is returned to the sending device after passing through a data communications link or network. This test allows the comparison of a returned signal with the transmitted signal to determine if the signal is making its way through the communications link and how much signal it is losing upon its total trip.

A protective tube loosely surrounding an optical fiber, often filled with gel used as a protective coating. Loosetube cable designs are usually found in outdoor cables, not inside buildings.

Optical fiber that is carried loosely in a buffer many times the diameter of the fiber. Loose-buffered fiber is typically terminated with a breakout kit or a fanout kit and connected to a patch panel. Also known as loose buffer.

The attenuation of optical or electrical signal, normally measured in decibels (dB). With respect to fiber-optic cables, there are two key measurements of loss: insertion loss and return loss. Both are measured in decibels. The higher the decibel number, the more loss there is. Some copper-based and optical fiber

A calculation and allowance for total attenuation in a system that is required in order to ensure that the detectors and receivers can make intelligent decisions about the pulses they receive.

Describes a connection having poor efficiency with respect to loss of signal.

LSF (Low smoke and fume) American standard.
Many times will be confused with LSOH. LSF will reduce smoke but will still emit gases.

Ensure that the customer understands the difference between LSF and LSOH

Low Smoke Zero Halogen insulation (sheath), Also known as LSOH, LSHF, Low smoke.

Normal PVC (Polyvinyl chloride) sheaths emit dense smoke and corrosive gases when burning (max safe working temp 70°C).
LSOH emits considerably less smoke and fumes and has a safe working temp of 90°C.

LSOH cables will be used in areas of public access, such as schools, supermarkets, hospitals, etc, along fire escape routes, and where equipment is likely to suffer damage due to corrosive fumes.
Many times will be confused with LSF.

Ensure that the customer understands the difference between LSF and LSOH

(1) See media access control. (2) Abbreviation for moves, adds, and changes.

A sublayer of the OSI Data Link layer (Layer 2) that controls the way multiple devices use the same media channel. It controls which devices can transmit and when they can transmit. For most network architectures, each device has a unique address that is sometimes referred to as the MAC address.

Network-adapter cards such as Ethernet, Token Ring, and FDDI cards are assigned addresses when they are built. A MAC address is 48 bits represented by six sections of two hexadecimal digits. No two cards have the same MAC address. The IEEE helps to achieve the unique addresses by assigning the first half to manufacturers so that no two manufacturers have the same first three bytes in their MAC address. The MAC address is also called the hardware address.

See also media access control (MAC) address.

A major bend in an optical fiber with a radius small enough to change the angle of incidence and allow light to pass through the interface between the core and the cladding rather than reflect off it. Macrobends can cause signal attenuation or loss by allowing light to leave the optical fiber core.

Optical power loss due to large bends in the fiber.

A cross-connect for first-level backbone cables, entrance cables, and equipment cables. The main cross-connect is at the top level of the premises cabling tree.

A wiring arrangement that connects the telephone lines coming from outside on one side and the internal lines on the other. The MDF may be a central connection point for data communications equipment in addition to voice communications. An MDF may also carry protective devices or function as a central testing point.