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All Call
|
Allows simultaneous ‘talk’ to all intercom speakers.
Most commonly used with Lee Dan’s TEK-COM common
talk intercom system.
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Alternating Current (AC)
|
Differs from direct current (DC) in only one very
important point. It typically starts at zero, gradually increases to a
maximum, then gradually decreases to zero. This change is then repeated
in the opposite direction. Alternating current changes direction 60 times
per second.
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|
American Wire Gauge (“AWG”)
|
A standard system for designating wire diameter.
Most intercoms use 22 AWG (read “22 gauge”) wire, although the transformer
and door strike wiring is usually 18 AWG. The larger the number, the smaller
the wire diameter. Hence 22 AWG wire is thinner than 18 AWG.
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|
Ampere
|
The unit of current. One ampere is the current flowing
through one ohm of resistance at one volt potential. Analogous to gallons
of water flow past a given point.
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|
Audio Frequency
|
The range of frequencies audible to the human ear.
Usually 20-20,000 Hz.
|
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Buried Cable
|
A cable installed directly in the earth without use
of underground conduit. Also called “direct burial cable.”
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Cabling
|
The twisting together of two or more insulated conductors
to form a cable.
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|
Call Tone
|
Electronic tone signal which sounds when a remote/sub
station calls a master station.
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|
Capacitance
|
Ratio of the electrostatic charge on a conductor
to the potential difference between the conductors required to maintain
that charge.
|
|
Circuit
|
Path through which electrical energy flows to and
from the source to the devices being operated.
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Coaxial Cable
|
A cable consisting of two cylindrical conductors
with a common axis, separated by a dielectric. Generally used to carry
video signals. See Lee Dan model RG-59U.
|
|
Color Code
|
A system for circuit identification through use of
solid colors and contrasting tracers or striped conductors.
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|
Common Wire(s)
|
Common wires may be looped/connected from station
to station (occasionally distance limitations may prevail).
|
|
Conductance
|
The ability of a conductor to carry an electric charge.
The ratio of the current flow to the potential difference causing the flow.
The reciprocal of resistance.
|
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Conductivity
|
The capacity of a material to carry electrical current—usually
expressed as a percentage of copper conductivity (copper being 100%).
|
| Conductor |
An uninsulated wire suitable for carrying electrical
current.
|
|
Conduit
|
A tube, pipe or trough in which insulated wire and
cables are run.
|
|
Continuity Check
|
A test to determine whether electrical current flows
continuously throughout the length of a single wire or individual wires
in a cable.
|
|
Coverage
|
The percent of completeness with which a metal braid
covers the underlying surface.
|
|
Crosstalk
|
Signal interference between nearby conductors caused
by pickup of stray energy.
|
|
C.S.A.
|
Abbreviation of Canadian Standards Association, a
nonprofit, independent organization which operates a listing service for
electrical and electronic materials and equipment. The Canadian counterpart
of the Underwriter’s Laboratories.
|
|
Current Carrying Capacity
|
The maximum current an insulated conductor can safely
carry without exceeding its insulation and jacket temperature limitations.
|
|
Desk Mount
|
A method to mount a station on a desktop, usually
with a sloping face, and generally using Lee Dan model IH-400A.
|
|
Direct Current (“DC”)
|
Term used to describe the flow of electrical current
in one direction only, uniform and continuous.
|
|
Door Station
|
A remote (sub) station located at a door or gate.
Usually weather resistant, available with or without a call button for
tone signalling. Communication is hands-free at the door, and controlled
by the indoor master.
|
Door Strike
(also Door Opener) |
An electro mechanical device used to unlock a door
from a remote location. Most popular is Lee Dan model DO-001.
|
|
Drain Wire
|
In a cable, the uninsulated wire laid over the component
or components and used as a ground connection.
|
|
Fail Safe
|
In a power down state, the device is unlocked or
unlatched.
|
|
Fail Secure
|
In a power down state, the device is locked or latched.
|
|
Flush Mount
|
A mounting method requiring a cutout be made into
the finished wall or other surface. Flush mounted equipment will be recessed
into the wall so the mounted object protrudes little from the face of the
wall (see ‘recessed’).
|
|
Gauge
|
Term used to denote the physical size of wire or
metal.
|
|
Ground
|
A conducting connection between an electrical circuit
and the earth or other large conducting body to serve as an earth thus
making a complete electrical circuit. The purpose is to minimize danger
from electrical shock and prevent lightning
|
|
Hands-Free Reply
|
Ability to reply to an incoming call from a master
station, without touching your intercom.
|
|
High Voltage
|
Generally, a wire or cable with an operating voltage
of over 600 volts.
|
|
Hook-Up Wire
|
A wire used for low current, low voltage (under 1000
volts) applications within enclosed electronic equipment.
|
|
Horizontal Mailbox
|
A multi compartment mailbox with deep ‘horizontal’
doors/compartments. Horizontal mailboxes generally require very deep walls
of 15" or more. Horizontals are more expensive than ‘vertical’ mailboxes,
but generally allow more boxes to be installed in limited wall (width)
space.
|
|
Housing
|
A mounting device used to install a station or panel.
There are three popular kinds; flush (recessed), surface, or desk mount.
|
|
Impedance
|
The total opposition that a circuit offers to the
flow of alternating current or any other varying current at a particular
frequency. It is a combination of resistance R and reactance X, measured
in ohms.
|
|
Insulation
|
A material having high resistance to the flow of
electric current. Often called a dielectric in radio frequency cable.
|
|
Jacket
|
An outer nonmetallic protective covering applied
over an insulated wire or cable.
|
|
Key Keeper
|
Used in buildings with mailboxes located behind a
locked entry door. This lock box is designed to hold the key to an apartment
or office building, for use by the local postal carrier. Always sold without
a lock. The (postal) lock is provided and installed by the local post office.
|
|
L.E.D. Annunciation
|
L.E.D.’s (light emitting diodes) used on a master,
under each selector button used to indicate which remote is calling a master.
Master operator then presses indicated selector button to control conversation.
|
|
Master Station
|
An intercom station which can both initiate and control
both elements (Talk, Listen) of a conversation.
|
|
Mortise
|
A notch or hole cut in a piece of wood or metal to
receive a projecting part shaped to fit.
|
|
Multiconductor
|
More than one conductor within a single cable complex.
|
|
Ohm
|
A unit of electrical resistance. Often written or
indicated by the Greek letter Omega.
|
|
Pedestal Mailbox
|
A multi compartment mailbox mounted on a steel or
other secure pedestal for outdoor use. Typically in condominium communities.
Deep doors/compartments are similar to ‘horizontal’ style mailboxes.
|
|
Postal Approved
|
Any mailbox approved by the Postmaster General of
The US Postal Service. Manufacturers must make detailed submittals to Washington
and conform to specific Size, Material, and Safety specifications.
|
|
Prefix Discounts
|
Generous discounts offerred by Lee Dan for customers
who purchase in quantity. Referred to as 'PREFIX' discounts because the
discount you earn is determined by purchasing a quantity of products with
the same 'PREFIX' (1st two letters of model number). For example, earn
discounts on as few as 10 'DO' (door openers).
|
|
Privacy
|
An intercom with privacy activated can receive calls
(listen), but the response is blocked for privacy.
|
|
Recessed
|
A mounting method requiring a cutout be made into
the finished wall or other surface. Recessed equipment will be recessed
into the wall so the mounted object protrudes little from the face of the
wall (see ‘flush’).
|
|
Rectifier
|
An electrical unit designed to convert alternating
current to direct current.
|
|
Remote Station
|
An intercom station which can respond to a call from
a master station. Remote stations may be equipped with a call button for
tone signalling only to a master station. Also commonly referred to as
‘sub station’.
|
|
Resistance
|
A measure of the difficulty in moving electrical
current through a medium when voltage is applied. It is measured in ohms.
|
|
Riser
|
A cable run used to connect a group of intercom stations.
Most commonly referred to in apartment intercom systems where ‘vertical’
risers are most common.
|
|
Selective Calling
|
Ability to call a specific intercom station by pressing
that station’s selector button. Communication at the calling master is
push to talk, release to listen. The called station may communicate hands-free.
|
|
Selective Wire(s)
|
Selective wires are used to uniquely identify a specific
intercom station.
|
|
Shield
|
In cables, a metallic layer placed around a conductor
or group of conductors to prevent electrostatic or electromagnetic interference
between the enclosed wires and external fields.
|
|
Sub Master
|
Hybrid intercom station which, like any remote (sub)
station can receive a call from a master, but may additionally be able
to make an All Call, and/or answer a call from a door station. Most common
in Lee Dan’s TEK-COM common talk intercom system.
|
|
Sub Station
|
An intercom station which can respond to a call from
a master station. Sub stations may be equipped with a call button for tone
signalling only to a master station. Also commonly referred to as ‘remote
station’.
|
|
Surface Mount
|
A mounting method utilizing the finished surface
of a wall as the anchor point. Surface mounted stations or panels will
protrude their full depth from the face of the wall.
|
|
Switch
|
A device placed in an electrical circuit in order
to make or break the flow of electrical current.
|
|
Transformer
|
A device for transferring energy in an alternating
current system from one circuit to another. Thus energy at high voltage
may be transformed to energy at low voltage and vice-versa. Most intercom
applications operate at low voltage, and thus require a “step down” transformer
to reduce voltage to system specifications (most typically 16 or 24 volts).
|
|
Twisted Pair Cable
|
Cable with individually twisted pairs of wires within
a single jacket.
|
|
UHF
|
Abbreviation for ultra high frequency, 300 to 3,000
Mhz.
|
|
U.L.
|
Abbreviation of Underwriter’s Laboratories, a nonprofit,
independent organization which operates a listing service for electrical
and electronic materials and equipment.
|
|
USPS
|
U.S. Postal Service
|
|
Vertical Mailbox
|
A multi compartment mailbox with tall ‘vertical’
doors/compartments. “Verticals” are less expensive than ‘horizontal’ mailboxes,
but generally require more wall (width) space, and are not usually suited
for larger installations (100+ compartments).
|
|
VHF
|
Abbreviation for very high frequency, 30 to 300 Mhz.
|
|
Voltage
|
The term most often used in place of electromotive
force, potential difference, or voltage drop to designate the electric
pressure that exists between two points and is capable of producing a current
when a closed circuit is connected between two points. Analogous to the
pressure in the water pipes of your home.
|
| Voltage Rating |
The highest voltage that may be continuously
applied to a wire in conformance with standards or specifications. |
Lee
Dan Home | Table
of Contents |