Calling partywikipedia
The calling party (in some contexts called the "A-Number") is a person who (or device that) initiates a telephone call.
calling partycallercall originatorcall sourcecall

Telephone call

telephone callcallphone call
The calling party (in some contexts called the "A-Number") is a person who (or device that) initiates a telephone call.
A telephone call is a connection over a telephone network between the called party and the calling party.

Called party

called partycalleecall receiver
The person who, or device that, receives a telephone call is the called party.
The person who (or device that) initiates a telephone call is the calling party.

Calling-party camp-on

* Calling-party camp-on
Such systems may or may not issue a system blocking signal to inform the calling party of the access delay.

Sports radio

Sportssports radiosports talk
A widespread programming genre that has a narrow audience appeal, sports radio is characterized by an often-boisterous on-air style and extensive debate and analysis by both hosts and callers.

Toll-free telephone number

toll-free telephone numbertoll-freetoll-free number
For the calling party, a call to a toll-free number from a landline is free of charge.

Direct distance dialing

direct distance dialingdirect dialdirect distance dial
Direct distance dialing (DDD) is a telecommunication service feature in which a caller may, without operator assistance, call any other user outside the local calling area.

Telephone number

telephone numberphone numbertelephone numbers
Telephone numbers are entered or dialed by a calling party on the originating telephone set, which transmits the sequence of digits in the process of signaling to a telephone exchange.

Caller ID

caller IDcaller line identificationCLI
Caller ID (caller identification, CID), also called calling line identification (CLID), Calling Line Identification (CLI), calling number delivery (CND), calling number identification (CNID), calling line identification presentation (CLIP), or call display, is a telephone service, available in analog and digital telephone systems, including VoIP, that transmits a caller's telephone number to the called party's telephone equipment when the call is being set up.

Distinctive ring

distinctive ringringing pattern
Regardless of what ringing pattern the called party hears, the calling party hears the standard ringing pattern.

Zenith number

ZenithZenith" X-XXXXWX number
A Zenith number was a special type of telephony service which allowed a calling party to call the number's owner at no charge by requesting the call from a switchboard operator and citing the "Zenith", "Enterprise" or "WX" number.

Call origination

Call origination, also known as voice origination, refers to the collecting of the calls initiated by a calling party on a telephone exchange of the PSTN, and handing off the calls to a VoIP endpoint or to another exchange or telephone company for completion to a called party.

Operator assistance

operator assistanceoperator-assistedperson-to-person
Operator assistance refers to a telephone call in which the calling party requires an operator to provide some form of assistance in completing the call.

Busy signal

busy signalengaged tonebusy
A busy signal (or busy tone or engaged tone) in telephony is an audible or visual signal to the calling party that indicates failure to complete the requested connection of that particular telephone call.

Call-progress tone

call-progress tonetonesNumber unobtainable tone
The tones are generated by a central office or a private branch exchange (PBX) to the calling party.

Collect call

collect callcollect1800 Reverse
A collect call in Canada, Pakistan, and the United States, known as a reverse charge call in other parts of the English-speaking world, is a telephone call in which the calling party wants to place a call at the called party's expense.

Automatic number identification

automatic number identificationANIthe caller's number
Modern ANI has two components: information digits, which identify the class of service, and the calling party billing telephone number.

Misdialed call

wrong numbermisdialled callsmisdialed call
The recipient of a wrong number is usually unknown to the caller.

Telephone exchange

telephone exchangeexchangescentral office
When a calling party lifted the receiver, the local loop current lit a signal lamp near the jack.

Last-call return

last-call return*691471
The service may also offer the facility to place a call to the calling party.

Switchboard operator

telephone operatorswitchboard operatoroperator
With the development of computerized telephone dialing systems, many telephone calls which previously required a live operator can be placed automatically by the calling party without additional human intervention.

Request line

request linecontest line
If there are no open lines, the calling party may receive a busy signal as with an ordinary telephone call, or sometimes the special information tones followed by a recorded announcement that "all circuits are busy, please try your call again later".

Dual-tone multi-frequency signaling

DTMFtouch-tonetouch tone
Prior to the development of DTMF, telephone numbers were dialed by users with a loop-disconnect (LD) signaling, more commonly known as pulse dialing (dial pulse, DP) in the U.S. It functions by interrupting the current in the local loop between the telephone exchange and the calling party's telephone at a precise rate with a switch in the telephone that is operated by the rotary dial as it spins back to its rest position after having been rotated to each desired number.