Simply put, a phone call in which only one half of the conversation is heard. This trope is sometimes used in conjunction with a NoodleIncident or NoodleImplements (see the ''SaturdayNightLive'' example below).

It can involve RepeatingSoTheAudienceCanHear, if the audience is intended to understand both sides of the conversation. Alternatively, the audience can be deliberately left in the dark and forced to imagine what the person on the other end is saying. This can lead either to drama and tension, or to [[HilarityEnsues hilarious misunderstanding]].

Alternatively, both halves of the conversation may be heard, per se, but from the audience's perspective, the words being spoken [[TheVoice by the person on the other end of the line]] come through as comically sped-up babbling or some other form of [[TheUnintelligible unintelligible gobbledygook]] (sometimes done to hide [[GettingCrapPastTheRadar really vulgar language]]).

[[TropeNamer Named]] after Bob Newhart, who used it in his RecordedAndStandUpComedy routines in the 1960s as well as some of his works below.

[[folder:Fan Fic]]
* In the ''Franchise/YuGiOh'' fic [[ "Loaded Bones"]], Bakura rings Marik to find out whether his SuperPoweredEvilSide is having him on about having used their shared body to have sex with Marik. Marik's side of the conversation isn't given, but is implied by Bakura's (mainly flustered) responses.

* In ''Film/DrStrangelove'', we hear President Muffley's side of his call to Soviet Premier Kisov explaining [[ApocalypseHow the situation]]. From the way Muffley has to keep explaining things in simple terms and nudging the conversation back on topic, it's clear that (as the Soviet ambassador warned) Kisov is [[VodkaDrunkenski thoroughly drunk]].
* ''Film/HellIsForHeroes'' is a 1962 film about WWII [=GIs=] who have to hold an outpost until their relief arrives. They occupy an abandoned German pillbox with a microphone linked back to enemy headquarters. Bob Newhart plays an army clerk who makes fake radio reports so the Germans will believe that the squad is bigger than it is. Many of them are quite funny.

[[folder:Live-Action Television]]
* Practically OnceAnEpisode in ''Series/TheBobNewhartShow'', and a RunningGag in ''Series/{{Newhart}}''.
* ''Series/SaturdayNightLive'' in the 1970s did this at the beginning of Weekend Update with Chevy Chase, in which Chase would be on the phone with a woman, talking about a bizarre medical condition, sexual act, or [[NoodleIncident something that happened that isn't described in full detail]] before realizing he's on camera and hangs up.
* ''Series/{{Supernatural}}''. While Dean is saying on the phone "It totally rocked my understanding of the word 'necrophilia'," a passing woman shoots him a look of disgust.
* Referred to on ''Series/MysteryScienceTheater3000'' when Mike refers to an uneventful scene of a man talking on the phone as "the unfunny half of a Bob Newhart routine''.
* A particularly hilarious one from ''Series/{{Coupling}}'':
-->'''Steve''': Jeff, calm down. Jeff, just listen, okay. Three things. One, you should not be using your mobile phone on an plane. Two, the name of the island is pronounced Les''bos''. ({{beat}}) Yeah, well that was fairly optimistic of you, wasn't it. Three, the behaviour of breast implants at altitude isn't a subject I can claim great knowledge on. ({{beat}}) Yeah, I'm fairly sure you can't raise it with a complete stranger. ({{beat}}) No, whatever danger you think she's in. ({{beat}}) No Jeff, not even with the people in "shrapnel range"! Okay, look, I'm going to hang up now. ({{beat}}) Because I don't want to endanger a planeload of innocent passengers by prolonging a conversation about the hazards of breast inflation.

* "Shriner's Convention by Music/RayStevens consists of a one-sided dialogue, via hotel phone, between two members of the Hahira, Georgia, delegation: leader "Illustrious Potentate" (Bubba), and member "Noble Lumpkin" (Coy). Over the course of the conversation we hear from Bubba about Coy's various exploits which include getting his Harley-Davidson motorcycle into his hotel room and on the high diving board of the hotel swimming pool, and his girlfriend streaking through their banquet yelling out the "secret code," wearing nothing but Coy's fez.
* Multiple Music/MindInABox songs have one-sided phone conversations with Black talking to his supervisor, White, on the other line. ''Forever Gone'' in particular is almost entirely a Newhart phonecall as Black reports his progress while tracing a target.

[[folder:Pro Wrestling]]
* One of the regular skits on GLOW were the ''Easy As KGB'' segments, featuring Col. Ninotchka (a typical anti-American Russian wrestler) on the phone with her very stupid subordinate, Vladimir.
* Paul E. Dangerously (a young pre-ECW Paul Heyman) used to regularly carry a cell phone with him at all times in WCW, sometimes talking to someone while a match was in progress. Naturally, only his half of the conversation got shown on TV.

[[folder:Stand-Up Comedy]]
* Bob Newhart had a lot of routines using this, perhaps the most memorable of which is his ''[[Film/KingKong1933 King Kong]]'' routine, in which a security guard at the Empire State Building's first night on the job is interrupted by the ape's ascent. Listen to it [[ here]].
* Lily Tomlin's Ernestine character was a telephone operator. Audiences heard only her half of her conversations.
* Shelly Berman was good at this sort of thing. His most famous bit was ''[[ The Morning After The Night Before]]'', where he calls his friend after a wild party, and hears about his unremembered drunken behavior.
* Creator/AlanBennett's 'Telegram' sketch, in which he attempts to dictate a telgram he wishes to send to the operator over the telephone and keeps being sidetracked.

[[folder:Video Games]]
* ''VideoGame/MetalGearSolid'' does this [[{{Stinger}} after the credits roll]], with a conversation between Revolver Ocelot and [[spoiler: the President, a.k.a., Solidus Snake]].

[[folder:Western Animation]]
* ''WesternAnimation/RobotChicken'': In the ''StarWars'' episode, Palpatine is on the phone with Vader when Vader tells him that the Death Star blew up. Palpatine is angry with Vader and makes Vader cry over losing Padmé.
** Also used in a skit where [[InspectorGadget The Claw]] learns that his cat is dying of cancer.

* Happens all the time when someone you're in the room with answers a phone.
* In some online forums, you can block a particular person so that they cannot send you messages and you cannot see anything they post. When other people do not have them blocked, it can create surreal situations where you see people replying to posts you can't see, leaving you to guess what the blocked person is saying. If one of the other people are feeling [[ItAmusedMe particularly puckish]], they might invoke this trope, replying to imagined comments instead of real ones because they know you can't tell the difference.