INOP  Inoperative;.not.working. 
INPH  Interphone 
INS  Inertial.Navigation.System..A.self-contained,. 
dead-reckoning.system.that.senses.the. 
acceleration.along.the.three.axes.of.the.aircraft. 
and.calculates.the.distance.traveled.from. 
a.reference.point..Accuracy.of.the.system. 
decreases.with.respect.to.time. 
INST  Instrument 
INTC  Intercept 
Interknit  Internet.Network.Information.Center 
INTERS  Intersections 
Intruder  An.altitude.reporting.aircraft.that.is.being. 
considered.as.a.potential.threat.and.processed. 
by.the.threat.detection.logic.(TCAS). 
Inverse Video  A video display technique that surrounds 
characters.or.digits.with.a.color.rather.than. 
creating.those.characters.or.digits.from.a.color. 
(i.e.,.black.characters.are.created.by.a.red. 
background.rather.than.writing.red.characters). 
I/O  Input/Output. Refers to bi-directional data ports. 
IOC  ( 1 ) Initial Operational Capability. 
( 2 ) Input/Output Concentrator. 
( 3 ) Input/Output Controller 
ION  Institute.of.Navigation 
IOR  Indian Ocean Region 
IOS  Internet Operating System 
IOT&E  Initial Operational Test and Evaluation 
IP  (.1.).Instructor.Pilot.. 
(.2.).Intermediate.Pressure.. 
(.3.).Internet.Protocol.. 
(.4.).Intellectual.Property 
IPACG  Informational Pacific Air Traffic Control 
Coordinating.Group 
IPB  Illustrated.Parts.Breakdown 

IPC  (.1.).Illustrated.Parts.Catalog. (.2.).Integrated.Processing.Cabinet. (.3.).Intermediate.Pressure.Compressor
IPD  (.1.).Industrial.Products.Division. (.2.).Integrated.Product.Delivery
IPI  Initial Protocol Identifier
IPL  Illustrated.Parts.List
IPM  Integrated.Performance.Management
IPR  Internet.Protocol.Router
IPS  In-Plane-Switching
IPT  (.1.).Intermediate.Pressure.Turbine..
(.2.).Integrated.Product.Team
IR  Infrared
IRD  Integrated.Receiver/Decoder
IRE  Internal.Roll.Extrusion
IRP  Integrated.Refuel.Panel
IRS  (.1.).Inertial.Reference.System.
( 2 ) Interface Requirements Specification
IRU Inertial.Reference.Unit