Craig Communications business telephone systems guide to Telephony definitions

Business Phone Systems, Phones and Components

Most Major Brands, Refurbished & New at Wholesale Prices with one Year Warranty
Click Here for an Online Phone System Request
or Call Us Toll Free: 800-306-3377
business phone system new and used sales with warranty replacement phones and parts
Aastra
AT&T
Avaya
ClearOne
Cloud Phones
Comdial
ESI
GN Netcom
Intertel
Iwatsu
Jive Communications
Lucent
Macrotel
Mitel
Music on-hold
NEC
Nitsuko
Norstar
Nortel
Panasonic
PanTerra
Plantronics
Polycom
Samsung
ShoreTel
Snom
Star2Star
S.W. Bell
Toshiba
Trillium
Vodavi
VoIP

Telephone terms and definitions

2500 (Set or Phone)
Usually refers to a basic single line phone.

66 Block
A block of connectors where phone wires are connected to. Usually a 25 pair amphenol cable goes from the KSU to the 66 Block.

Amphenol
Refers to the plug found on 25 pair cables used in telephone wiring. Sometimes found in other sizes like 18 pair.

Analog
Short for analogous or "similar to". Refers to telephone transmission and/or switching which is not digital. Analog transmission of sound or information uses "waves" of electricity, converting sound waves to electrical waves.

Auto Answer
The capability of a terminal, modem or a computer to answer a call and set up a data connection without anyone being there.

Auto Attendant
A device or a feature of some voice mail units that answers a call and lets the caller route their call to a specific extension or group.

Auto Transfer
Feature switches un-answered incoming calls to a back-up position after a pre-determined interval of time. (If a call is not answered at station X, after a set time limit, the call is transfered to Y).

ACD
Auto Call Distribution. A specialized phone system used for handling many incoming phones which distributes the calls in a logical pattern. (If calls are coming in slowly they won't always ring at the same location keeping one secretary busy while the others read the morning paper).

Battery Backup
Retains program if power is lost. Larger units can keep the phone system running for a few hours without power.

BLF
Busy lamp field. Shows what other extensions are already using the phone.

Board
Card, Printed Circuit Board (PCB).

Butt-Set
The test phone used by telephone installers.

Cabinet
The electrical box that contains the boards. Usually called the Key Service Unit (KSU).

Call Forwarding
Feature which allows an incoming call to be sent elsewhere.

Card
The PCB that plugs into the control unit or cabinet. CPU card, Station card, CO card, etc...

CAT 3 Cable
Up to 25 Mhz communication.

CAT 5 Cable
Up to 100Mhz communication.

Centrex lines
Service offered by the phone company. Provides single line service with many more features. Typically, the user must sign a 3,5, or 7 year contract and can save up to 35% on business phone lines. You need to dial 9 to get an outside line.

CO
Central Office. Provides phone lines to your home or business, with a limited number of phone coverage. (Your ordinary, basic phone line).

Conferencing
Connecting 3 or more people into one phone conversation whether inside or outside the system. Different phone systems can handle a different quantity of simultaneous conference calls.

Cord
Refers to handset cord ( the curly cord that goes from the phone to the handset), line cord ( the flat cord between the wall jack and the phone). Line cords come in 2, 4, 6, and 8 conductor leads.

CPU
Central Processor Unit. Controls system functions. Also, referred to as the Central Processor Board (CPB), Enhanced Processor Board (EPB) or ECPU. (The brains of a system).

CRT
Cathode Ray Tube. A terminal used for programming or in some instances, to view and answer calls. (Your basic monitor).

Data Port
Point of access to a computer that used trunk or lines for transmitting or receiving data. A phone can have a data port which allows you to connect another phone related device such as a fax or modem.

Default
To return the system to its basic initial program.

Desi
The paper strip where you write the telephone number or extension. Also called designation.

Dial Tone
The tone that is heard when accessing an outside line. The same tone you hear when picking up your home phone.

DID
Direct Inward Dial. Dialing a number to reach a specific person or department. That call would only ring at the specified phone.

Digital
In recording, the use of binary code to represent information. More accurate form of transmitting information. Digital transmission of sound or information breaks down a "sound wave" into tiny sections of (1's and 0's code). The code then needs to be built back into a "wave" at the recieving end. Data is less susceptible to interference because electrical "noise" does not build up the signal wave.

DISA
Direct Inward Station Access. A person can call into the system, from away, and access the system to make intercom calls or call back out on another line.

DND
Do Not Disturb. Most phone systems have this feature to stop incoming calls and intercoms.

DSS
Direct Station Selection. Access another station with one key press, and view who is already on the phone. (see BLF). Usually a free standing phone unit. Some phones have DSS keys.

DTMF
Dual Tone Multi Frequency. Tones that are heard when dialing on an outside line or single line phone.

End User
If you don't know it's because you are one. (The user who ends up using the items purchased by a wholesaler or interconnect).

EPROM
Electrical Programmable Read Only Memory. Software is stored in these chips, and they will not loose there information with a power loss. Can be erased with ultra-violet light and reprogrammed many times.

EEPROM
Electrical Erasable Programmable Read Only Memory. Same as above but can be erased elecrically.

Extension
A unique number that identifies a phone. Extension numbers usually start with 10, 20, 100 ,301, 3001. Sometimes referred to as an intercom number.

Ground Start
A way of drawing dial tone by grounding one lead on the CO card.

Handsfree
Talking on the phone without picking up the handset. You may have handsfree on intercom but not on an outside line. A true speakerphone can communicate on an outside line without lifting the handset.

Hookswitch
Mechanical or electrical switch used to terminate a call. The handset usually depresses the hookswitch when it is returned to the cradle.

Intercom(ICM)
The way inside callers communicate to other "inside" people using their phones.

Installation
The physical hook-up and diagnostic testing of a PBX switch, cabinet, or peripheral item prior to a cutover and maintenance acceptance by the maintaining vendor. (Basically,plugging all your phones into the KSU and programming it so all the telephones work properly).

Interconnect
A company that sells, installs and maintains telephone systems for end users. The larger ones carry inventory and have a technical staff. What's an "end user"? if you don't know it's because you are one. (The user who ends up using the items).

Keyset
Telephone instrument. (multi line) Also known as "Voice terminal." (Your basic business phone.) Don't try plugging one in at home, or a home phone inplace of a keyset. They may look the same but they are completely different!

KSU
Key Service Unit. The main cabinet that holds the cards, or self-contained units. Most multi-line phones plug into a KSU. The KSU controlls all the calls, which phones ring at certain times, and everything else your phone system does.

Last Number Redial
Hit a button and the phone will redial the last number dialed.

LCD
Liquid crystal display, usually called a display phone. Can be added to some phones when needed. Usually displays the time, extension number, and other usefull information.

LCR
Least Cost Routing. Feature that automatically chooses the lowest cost phone line to the destination.

Lines
The lines that come into your building from the phone company. CO line or trunk line.

Line Cord
The cord that goes from the wall to the phone.

Loop Start
A way of drawing dial tone by completing an electrical loop on a CO port.

MDF
Main Distribution Frame. The panel where cables from the KSU are terminated. (A mess of wires where the phone lines get attached to the KSU).

Message Waiting
A light on the phone indicating there's a message for the user of the phone, either on a voice mail or from another extension.

Modems
Equipment which converts digital signals to analog signal and vice-versa. (Hmmm.... and I thought it was a device that communicates (usually over a phone line) with another device (modem) to transfer data. Well... it converts digital 1's and 0's to a loud noise, transmits it over the phone to another modem that converts the noise back into 1's and 0's.

Modular Cord
A cord that has plastic clips on the ends. As opposed to one that is permanently hardwired in.

Modular Jack
The outlet where a telephone is plugged into (RJ11). 

Music On Hold
Background music heard when someone is put on hold. Can be pre-recorded or from radio stations.

OHVA
Off Hook Voice Announce. Allows someone to intercom you while you are on the phone with someone else and use the speaker and microphone to communicate.

OPX
Off Premises Extension. Having a phone connected to your phone system that is usually not in the same building.

Options
Features that are activated on some systems. (Special stuff that you have to pay extra for, even though the hardware and software are usually already there).

Paging
Upon dialing an appropriate code, any station may make a paging announcement through all of the loudspeakers and other phones.

PBX
Private Branch Exchange. A switch used inside a private business as opposed to one serving the general public. Various manufactures have different names for these such as: PABX, CBX, EPABX, etc.. Most systems require dialing 9 to get an outside line.

PCB
Printed Circuit Boards or "Card" (The thing with all the colorfull little doo-hickies and little black boxes that make it work).

Port
A spot where you plug in a phone or a CO line. (A station card may have 4, 6, 8, 12 etc... ports).

Punch Down Tool
The tool used to punch down phone wires onto a 66 Block.

Reset
Unplugging or momentarily turning off the power to a device. Some KSU's have a reset switch. This sometimes needs to be done if the KSU has been bad or gotten confused and doesn't work properly.

Ring Gen (90 VAC)
A device that produces 90-110 Volts AC. Used to ring a single line device.(Voice Mail, Auto Attendant) ALL regular phone devices like fax machines, answering machine, home phone etc.. need aprox. 100vAC at 30Hz to ring. Business phone systems use a low DC voltage signal to tell the phone to ring.

RJ11
The modular jack where phones or devices are plugged in (wall jack). 
RJ11 = 4 conductor.
RJ12 = 6 conductor.
RJ45 = large 8 conductor.

Rotary Dial
Remember your grandparents phone where you had to spin the wheel to get it to work. Well rotary dialing uses a sequence of pulses to represent different numbers that are dialed. (If you were quick enough you can rapidly hit the hookswitch 8 times to signify an 8 in a phone number).

Single Line
A phone that can only access one line. Your home phone is a single line Phone.

S/L port
A port on a card that will run single line phones.

Software
The instructions the CPU uses to perform tasks. Stored on disks or chips (EPROMS).

Speakerphone
Feature which allows the operator to converse with another party either inside the system or outside without picking up the handset.

Stations
The ports or the telephone instruments. The different plugs you can connect a business phone to on your KSU. Station 100, 101 etc...

Touch Tone
The tones that are generated when dialing out or pressing a number on the dial pad (DTMF).

Trunk
The phone line from the phone company. Can be ground start or loop start. (Don't let this ground and loop stuff confuse you too much).

Transfer
Most phone systems have the ability to transfer calls to another phone somewhere in the building. Transferring calls usually puts the caller on exclusive hold and rings the phone it was transferred to. Supervised transfer is when you are able to announce the call to the station being transferred via the intercom function. A blind transfer is when the call is transferred and simply rings at the new station.

Version
When new features are introduced or problems resolved, the software version changes.

Voice Mail
A device (usually a computer) that answers calls and allows the caller to leave a message, gives the ability to send inter-office messages to groups, allows employees to retrieve messages from both inside and outside the office and has an auto attendant feature.

Yellowed
Plastic can turn yellow over the years when exposed to direct sunlight and/or florescent lighting. White plastic is effected the most, however other colors can be effected as well.




PROUDLY SERVING CUSTOMERS
FOR OVER 18 YEARS


Learn More About
VoIP Phone Hosted Cloud
Solutions for your Business.

More details »

Search for Phone
System Equipment
Make & Models Below:



WE BUY Phone Systems!
More details »
Testimonials from our
happy customers »

Dont See What You
Are Looking For?
Click Here »