A ghost call or phantom call is a

telephone call A telephone call is a connection over a telephone network between the called party and the calling party. First telephone call The first telephone call was made on March 10, 1876, by Alexander Graham Bell. Bell demonstrated his ability to " ...

for which, the recipient of the call answers, however there is no one on the other end of the call. The term is also used in managing

IP PBX An IP PBX ("Internet Protocol private branch exchange") is a system that connects telephone extensions to the public switched telephone network (PSTN) and provides internal communication for a business. An IP PBX is a PBX system with IP connectiv ...

systems. Ghost calls on the lines that cannot be explained or are some residual output of one

Real-time Transport Protocol The Real-time Transport Protocol (RTP) is a network protocol for delivering audio and video over IP networks. RTP is used in communication and entertainment systems that involve streaming media, such as telephony, video teleconference applicati ...

or RTP stream interacting with the PBX. Ghost calls differ from

silent calls A silent call is a telephone call in which the calling party does not speak when the call is answered. Most such calls are generated by a cold call telemarketing operation's predictive dialer which makes many calls, and sometimes does not have a ...

which tend to be from telemarking organisations with no agents available to speak at the time an automated call has been placed.

Causes

Ghost calls are generally caused by a neglected

autodialer An automatic dialer (also spelled auto dialer, auto-dialer, and autodialer) is an electronic device or software that automatically dials telephone numbers. Once the call has been answered, the autodialer either plays a recorded message or connec ...

or indirectly as a consequence of restrictions applied to autodialers used for

telemarketing Telemarketing (sometimes known as inside sales, or telesales in the UK and Ireland) is a method of direct marketing in which a salesperson solicits prospective customers to buy products or services, either over the phone or through a subseque ...

by agencies such as the

FCC The Federal Communications Commission (FCC) is an independent agency of the United States federal government that regulates communications by radio, television, wire, satellite, and cable across the United States. The FCC maintains jurisdictio ...

that restrict how long they can tie up a phone line; the call is disconnected automatically at the calling end. Another cause is

port scanning A port scanner is an application designed to probe a server or host for open ports. Such an application may be used by administrators to verify security policies of their networks and by attackers to identify network services running on a host a ...

.Tyler Kunkel
"Identifying/Stopping 'Phantom' or 'Ghost' calls"
Spectrum VoIP, August 15, 2019. Ghost calls can also be caused by accidental

pocket dialing Pocket dialing (also known as pocket calling or butt dialing) is the accidental placement of a phone call while a person's mobile phone or cordless phone is in the owner's pocket or handbag. The recipient of the call typically hears random backgr ...

Consequences

A ghost call sometimes can be repetitive or completely tie up a phone line, making it impossible to call 911 in case of emergency. In some cases an auto-dialer may be overlooked or even abandoned. This tends to happen very rarely.

Stopping the calls

Several websites collect reports of ghost calls. Repeated reports of the same number provide insight into where the machine is located and hopefully aid in having it shut down.

Improvements

Today's autodialer supposedly runs a smarter software, claiming a less than 2% hangup rate. However, most telemarketing companies place thousands of calls an hour, bringing that 2% back up to an annoying level.

References

{{Reflist Telephony