key lockout

- keyboard lockout

- acoustic alarm system
- acoustic image system
- acoustic systems
- actiontrack system
- active IR-system
- actuator system
- adaptive communication system
- adaptive teleinformation system
- adaptive telemetering system
- advanced information system
- Afsatcom system
- air system
- aircraft intercommunication system
- airfield communication system
- air-ground automatic system
- airline reservation system
- air-to-ground TV system
- alarm signal system
- alarm system
- all-channel signaling system
- ALL-IN-ONE system
- alphanumeric system
- amplified speaker system
- amplitude shift-keying system
- AMPS system
- analog cellular communication system
- analog cellular system
- analog component video system
- analog television system
- analog tropospheric system
- anisochronous system
- antenna system
- antitheft system
- AR system
- Arabsat system
- ASK system
- associated channel analog system
- asynchronous address communication system
- audio recording system
- Aurora system
- Aussat system
- automatic communication system
- automatic connection establishment system
- automatic control system
- automatic data acquisition system
- automatic telegraphy system
- automatic telephone system
- automatic tuning system
- automatized cellular system
- auxiliary alarm system
- balanced cable transmission system
- band sharing system
- base station system
- baseband system
- basic input/output system
- bass-reflex speaker system
- batch processing system
- batch transmission system
- batch-and-forward system
- batteryless system
- bilateral CTV system
- binary tariff system
- biocontrol system
- bit parallel interface system
- bit transport system
- bridge duplex system
- broadband mobile system
- broadcast satellite system
- broadcasting delivery media systems
- burglar alarm system
- byte-serial interface system
- cabinet system
- cabinetless system
- cable distribution system
- cable TV system
- call-accounting system
- call-answering system
- call-counting system
- call-distributing system
- call-processing system
- call-queueing system
- camp-on system
- CAPTAIN system
- car component audio system
- carrier reinsertion system
- carrier system
- carrier-communication system
- carrier-current communication system
- Cassegrain-Schmidt system
- cassette recording system
- cassette reproducing system
- CATRIN system
- caution system
- CD 900 system
- cellular system
- cellular-radio system
- central-battery system
- centralized control system
- chirp binary telegraph system
- cipher system
- circuit switched telecommunication system
- circuit switching telecommunication system
- circular telecontrol system
- clock system
- closed-circuit communication system
- closed-circuit telegraph system
- closed-numbering system
- code-dependent system
- code-division multiple access system
- code-independent system
- code-insensitive system
- code-sensitive system
- coding system
- coherent fiber-optic system
- collimating system
- collocated system
- color separating system
- combined numbering system
- combined power supply system
- combined satellite communication system
- common-battery system
- common-carrier system
- common-channel signaling system
- common-engineering communication system
- common-purpose cellular system
- common-using band system
- common-using cordless telephone system
- common-using paging system
- communication system
- communication traffic system
- communications system
- community antenna system
- community antenna television system
- community TV-system
- commununication switching system
- compact disk digital audio system
- compatible color television system
- compatible single sideband system
- compatible single-band system
- compatible TV-system
- complex radio communication system
- computer vision system
- computer-telephone system
- Comsar system
- Comsat system
- Conax system
- concentrated-insonation system
- conference system
- conference-communication system
- congested system
- congress-class system
- constant-current system
- control generating system
- conventional television system
- Conversant system
- cordless-communication system
- crossbar system
- crossed-coincident microphone system
- Crosspoint system
- CSE system
- C-system
- cubical video projecting system
- data processing system
- data system
- data transport system
- data-collection system
- data-compression system
- data-exchange system
- dataflow system
- data-gathering system
- data-handling system
- data-measuring system
- data-reduction system
- data-transmission system
- Decca Navigator system
- DECfax system
- decision-feedback system
- dedicated control channel system
- dedicated multimedia system
- delta-sigma system
- deluxe presentation system
- departmental communication system
- desktop-video system
- DFS/Copernicus system
- dial-telephone system
- differential phase shift-keying system
- differential-duplex system
- differential-magnetic system
- digital camera system
- digital hybrid-key telephone system
- digital mass storage system
- digital microwave radio transmission system
- digital telephone communication system
- digital transmission system
- digital TV-communication system
- Digital UNIX system
- digital-analog system
- digital-cellular system
- digital-data modulation system
- digital-effect system
- digital-message entry system
- digital-termination system
- direct-broadcasting satellite system
- directing system
- direct-modulation system
- direct-sequence system
- direct-telephone communication system
- discrete communication system
- discrete sound system
- discrete-addressing system
- disk-operating system
- DISOSS system
- dispatch telephone communication system
- dispatch-center system
- dispersed-insonation system
- distributed-insonation system
- distributed-processing system
- documental-type communication system
- Dolby systems
- domestic satellite communication system
- double-band telephone communication system
- double-channel transmission system
- double-current transmission system
- double-pole communication system
- double-sideband large carrier system
- DSCS system
- D-system
- dual-cable system
- dual-reflector system
- duplexed system
- Earth-to-space transmission system
- ECM system
- electric communication system
- electronic antishock system
- electronic data-gathering system
- electronic data-processing system
- electronic-message system
- electronic-scanning system
- electronic-switching system
- Ellipso system
- emergency telephone communication system
- emergency-broadcast system
- EMX system
- equidistant system
- error-correction system
- error-detection system
- Eutelsat system
- extensible system
- external paging system
- facsimile system
- fast-acting servicing system
- fault-tolerant system
- fax communication system
- fax transmitting system
- feed system
- fiber transmission system
- fiber-optic transmission system
- field-sequential system
- final mile system
- finishing system
- fire alarm system
- fire warning system
- first generation cellular system
- five-channel communication system
- fixed satellite system
- Flexcam system
- flexible access system
- Flitsatcom system
- focusing system
- four-channel sound system
- four-dimensional system
- four-wire telephone communication system
- frame-sequential system
- frequency shift-keying system
- frequency-carrier system
- frequency-control system
- front-bass reflex speaker system
- fully digital system
- gate system
- Gaussian system
- generalized system
- generating dynamic system
- generator-dc-motor system
- GIGASET radio system
- global positioning system
- Global system
- Gopher system
- grandfathered system
- group-alerting and dispatching system
- guide system
- hard-wired CCTV system
- hazard system
- helical-scan system
- HF-synchronizing system
- high-precision navigating system
- Hi-linear system
- home system
- home-telephone system
- home-type system
- homing-guidance system
- host system
- hydroacoustic system
- ideal communication system
- idealized system
- image informaion system
- image-forming system
- immedial servicing system
- incompatible system
- independent system
- information retrieval system
- information system radio system
- information system
- information-feedback system
- information-measuring system
- infrared alarm system
- Inmarsat system
- Inmarsat-A system
- Inmarsat-B system
- Inmarsat-C system
- Inmarsat-D system
- Inmarsat-M system
- Inmarsat-P system
- integrated telephone system
- integrated videographic teleconferencing system
- integrated-antenna system
- integrated-communication system
- integrated-modulation system
- integrated-office system
- Intelsat system
- interactive system
- intercarrier-sound system
- intercommunication system
- intercontinental tropospheric system
- interlock system
- intermachine exchange system
- intermediate system
- international communication system
- interphone system
- Intervision system
- intraband signaling system
- intruder alarm system
- inward-outward dialing system
- ionoscatter system
- ionosphere sounder system
- ionospheric system
- Iridium system
- isolated system
- Italsat system
- J-carrier system
- joint-multichannel trunking and switching system
- K-carrier system
- key system
- key-telephone system
- land satellite communication system
- large-grained communication system
- laser communication system
- L-band satellite system
- L-carrier system
- Leasat system
- lightning protection system
- limited distortion system
- line amplifiers system
- link system
- little-channel relay system
- local alarm system
- local battery system
- local communication system
- local radio paging system
- long-haul system
- long-range system
- loop system
- loud-speaking communication system
- low-traffic system
- magnetic tape recording system
- Mail system
- management-information system
- manual cellular system system
- manual telephone set system
- Marisat system
- master television system
- master-antenna television system
- matrix sound system
- message feedback system
- message procession system
- message registration system
- message-switched system
- meteor radio system
- Metrobus system
- micro component system
- Micro Press Cluster Printing system
- micro-lens system
- microprocessor system
- microwave relay system
- midi system
- mine radio telephone system
- mini system
- mixed media system
- mixed numbering system
- mobile cellular communication system
- mobile land communication system
- mobile radio system
- mobile relay system
- mobile system
- modulated system
- monetary mobile system
- MS-Mail system
- multiareal system
- multicassette system
- multichannel telephone system
- multicomputer system
- multidisk system
- multiformat recording system
- multifrequency tone signaling system
- multiguard system
- multilevel mixed system
- multimedia system
- multiple-channel system
- multiqueue system
- Multiscrypt system
- multistandard system
- multitrack editing system
- mutibeam antenna system
- muting system
- Nagravision system
- NAMTS system
- narrow-angle TV system
- national communication system
- navigation system
- n-channel communication system
- n-channel DPSK system
- n-channel transmission system
- network standalone system
- network system
- network-operation system
- networks numbering system
- neutral direct-current telegraph system
- n-head video system
- NMT system
- noise-reduction system
- nonhoming tuning system
- noninterlaced television system
- nonsegmented system
- Norsat system
- n-satellite system system
- n-tone DPSK system
- n-tone MFSK system
- NTSC system
- NTT system
- obligatory message system
- Odyssey system
- off-line system
- on-line computer system
- on-line secured system
- open numbering system
- open system
- operative-engineering communication system
- opposite signals system
- optical-communication system
- optical-information system
- optical-projection system
- optoelectronic system
- oscillating system
- oscillation system
- outband signaling system
- package-and-resource tracking system
- pagemaster system
- paging system
- PAL system
- parametric system
- PATHWORKS system
- pattern recognition system
- personal holding guard system
- phase shift-keying system
- phone system
- Piccolo system
- pilot-controller system
- polar direct-current telegraph system
- portable mobile system
- power control system
- power controlling system
- power-line carrier system
- power-supply system
- press-to-talk system
- Prestel system
- primary-supply system
- privacy system
- private branch paging system
- private movable system
- private videodata system
- private videotex system
- process-interface system
- PROFS system
- programmable cross-connect system
- programmable cross-connected system
- programmed radio system
- prompting system
- protected wireline distribution system
- protection system
- pseudoquadraphony system
- pseudotrunking system
- public videodata system
- public videotex system
- pulse-code system
- pulse-frequency system
- pulse-time system
- quadraphonic sound system
- quadruple-diversity system
- R1 system
- R2 system
- radio buoy system
- radio command system
- radio communication system
- Radio Data system
- radio facsimile system
- Radiocom 2000 system
- radio-control system
- radio-paging system
- radio-relay system
- radiosonde-radio-wind system
- radio-telemetering system
- real time pulse-echo system
- real time system
- receiver lockout system
- recording system
- recovery system
- redundant system
- reference-information system
- regional electronic payment system
- relay-radio system
- remote concentrating system
- remote control system
- remote diagnostic system
- remote information system
- remote semiconcentrating system
- remote sensing system
- remote signaling system
- rendering system
- rerecording system
- reserved servicing system
- RF/Transmission system
- rotary system
- safety alarm system
- safety system
- Satcom system
- satellite comminication system
- satellite marine comminication system
- Satellite Master Antenna Television system
- satellite radio system
- satellite-aircraft communication system
- SB-communication system
- SBL communication system
- scalable system
- scanning trunking system
- SCO UNIX system
- searchless identification system
- seat reservation system
- SECAM system
- second generation cellular system
- second room system
- secondary supply system
- secrecy system
- section communication system
- security system
- segmented system
- seismic system
- selective calling system
- selective frequency base station system
- selective protective system
- selective telephone system
- self-adjusting system
- self-balancing differential system
- self-contained system
- self-test system
- selsyn system
- semiautomatic-switching system
- semiautomatized cellular system
- sensory system
- servo system
- shadow-batch system
- short-haul microwave system
- Sicral system
- Sigma Servo system
- signal system
- simplex movable system
- single-band transmission system
- single-busbar system
- single-cable communication system
- single-cable system
- single-channel system
- single-current transmission system
- single-pulse tracking system
- Skynet system
- small-grained communication system
- SmarTrunk II radio communication system
- solid-state uninterruptible power battery system
- Sony bus system
- sound alarm system
- sound equalization system
- sound navigation system
- sound reinforcement system
- sound warning system
- space-division system
- space-switched system
- spark-safe system
- speaker system
- special communication system
- speech-processing system
- speech-recognition system
- split-speaker system
- spread-spectrum system
- stabilizing system
- stage monitoring system
- standalone double point system
- star-circuit system
- STAREX CMX system
- starting communication system
- start-stop system
- stationary satellite system
- step-by-step system
- stereo sound system
- stereophonic sound system
- storage system
- storage-and-retrieval system
- Strowger system
- submarine fiber-optic system
- subprimary digital transmission system
- subscriber carrier system
- subscriber switching system
- suffix system
- Supersat system
- supervisory control system
- surround sound system
- switched telecommunication system
- switching system
- sync communication system
- synchro system
- synchronous communication system
- synchronous digital system
- TAGS system
- tandem system
- tariffication system
- T-carrier system
- TDF system
- teleautomatic system
- Telecom system
- telecommunication system
- telecommunications system
- telecommunication-service priority system
- telecommunications-service priority system
- telecontrol system
- telemechanic system
- telemetering system
- telemetry system
- telephone system
- telephone-answering system
- telephone-communication system
- telephone-communications system
- teleprocessing system
- Telesat system
- teletex system
- teletypewriter system
- television-telephone system
- Tele-X system
- Telsar system
- terminal system
- terrestrial radio-relay system
- theft-prevention system
- thin-route system
- third generation communication system
- three-axle stabilizing system
- three-channel HF-telephone system
- three-channel transmission system
- three-color system
- three-lens optical system
- three-primary system
- three-wire system
- time-dissemination system
- time-frequency hopping system
- time-switched system
- total access communication system
- total area coverage system
- transmission system
- trichromatic system
- triple-interlace system
- triplex system
- trunk communication system
- TV-observation system
- twelve-channel transmission system
- two-arm system
- two-band system
- two-color system
- two-roller transfer system
- two-step control system
- two-way CATV system
- two-way system
- two-wire telephone communication system
- ultra-match system
- ULTRIX system
- unified radioaccess system
- unilateral-control system
- unilateral-synchronization system
- uninterruptible-power system
- Unisat system
- universal alarm system
- universal-battery system
- universal-electronic system
- universal-movable system
- Uniworks system
- vestigial-sideband system
- video editing system
- video home system
- video recording system
- videocom system
- videoteleconference system
- videotex system
- virtual studio system
- vision system
- vocoder system
- voice dialog system
- voice frequency carrier telegraph system
- voice modulation system
- voice post system
- volume control system
- waiting system
- warning system
- watch system
- watching system
- waterside facsimile communication system
- wave-propagating system
- wide-angle TV system
- Winfax Pro system
- wired broadcasting system
- wireless CCTV system
- wireless home system
- wireless infrared speaker system
- wire-radio communication system
- XY system
- zone-selective protection system
- zoning system

- acknowledge switch
- acoustooptical Q-switch
- air pressure switch
- analog switch
- auto switch
- auto-manual switch
- automatic-manual switch
- autoretract switch
- binary switch
- blade breakage switch
- block skip switch
- block switch
- breakdown switch
- cam switch
- changeover switch
- coarse-fine switch
- control switch
- crossover switch
- cutoff switch
- cycle switch
- cycle-setting switch
- delay switch
- DIP switch
- directional switch
- direction-reversing switch
- disconnect switch
- double-trigger switch
- earthing switch
- electronic switch
- emergency limit switch
- emergency stop limit switch
- end-of-bar switch
- feed switch
- finger-tip switch
- fixed distance retract switch
- flowmeter switch
- foot switch
- foot-operated switch
- forward/reverse switch
- gang switch
- ganged switch
- gate-controlled switch
- grounding switch
- guard-locking switch
- home switch
- index switch
- inductive limit switch
- inductive switch
- insertion switch
- interlock switch
- isolating switch
- key selector switch
- key switch
- knife switch
- level switch
- lever switch
- load-dependent switch
- lockout switch
- magnetic flux sensitive switch
- main switch
- master electric switch
- matrix switch
- micro switch
- mirror image switch
- mode select switch
- mode switch
- momentary-contact switch
- multimode switch
- multiplex switch
- multiplexer switch
- multistep selection switch
- normally closed switch
- normally opened switch
- omnidirectional switch
- on-off software related switches
- on-off switch
- optical switch
- optomechanical Q-switch
- out-of-stock switch
- overload switch
- override switch
- padlockable switch
- pallet-presence switch
- passive Q-switch
- pendant switch
- piezopulse and mechanical switch
- position switch
- power cutoff switch
- power disconnect switch
- preset switchs
- press-at-any-point switch
- pressure limit switch
- pressure sensing switch
- programmable limit switch
- programmable off switch
- programmable on switch
- pushbutton switch
- Q-switch
- reed switch
- retract switch
- return switch
- reversing switch
- rotary switch
- safety cutoff switch
- safety pressure switch
- safety switch
- safety-interlock switch
- selection switch
- selective switch
- selector switch
- sensor switch
- silicon bilateral switch
- slide switch
- snap-action switch
- software switch
- software-defined switch
- softwire related switches
- softwired limit switch
- solid state switch
- speed-tension control switch
- spindle control switch
- spindle direction reversing switch
- spindle head switch
- spindle reverse switch
- starter switch
- stepping switch
- stop switch
- stop/start switch
- temperature limit switch
- thermal overload switch
- time delay switch
- toggle switch
- touch pad switch
- triple cam switch
- tumbler switch
- two-way switch
- unilateral switch
- video switch

- anechoic box
- anti-TR box
- anti-transmit-receive box
- ATR box
- attenuation box
- Bernoulli box
- bitty box
- black box
- blue box
- boom box
- bounding box
- breakout box
- brush box
- call box
- capacitance box
- capacitor box
- character box
- check box
- close box
- compatibility box
- condenser box
- current page box
- data switch box
- dead letter box
- dialog box
- decade box
- decision box
- DOS box
- drop-down list box
- echo box
- entrance box
- fade box
- function box
- fuse box
- ghetto box
- glove box
- gray box
- horizontal scroll box
- idiot box
- inductance box
- interactive set-top box
- iron box
- jack box
- junction box
- key box
- keyed S-boxes
- letter box
- lock box
- lockout box
- mail box
- morphological box
- music box
- outlet box
- process box
- resistance box
- S-box
- scroll box
- set-top box
- shadow box
- squawk box
- squeeze box
- storage box
- stunt box
- substitution box
- telephone box
- television set-top box
- terminal box
- TR box
- transmit-receive box
- tunable echo box
- twinkle box
- vertical scroll box
- virtual safe deposit box
- volt box
- voltage-ratio box
- web set-top box
- white box
- zoom box

- advance pulse
- alternating-current pulse
- anticoincidence pulse - bell-shaped pulse
- bidirectional pulses
- bipolar pulses
- blackout pulse
- blanking pulse
- brightening pulse
- call-indicator pulse
- carrier-frequency pulse
- carrierless pulse
- carry pulse
- channel pulse
- charge pulse
- chirp pulse
- clamp pulse
- clock pulse
- cloud pulse
- coincidence pulse
- comparison pulse
- compressed pulse
- constant-duration pulse
- convolved pulse
- dark-current pulse
- delta light pulse
- dial pulse
- digit pulse
- digit synchronizing-pulse
- disabling pulse
- discharge pulse
- disturb pulse
- disturbing pulse
- drive pulse
- driving pulse
- edit pulse - enabling pulse
- end-carry pulse
- equalizing pulse
- erase pulse
- error pulse
- execute pulse
- fast pulse
- feedback pulse
- field blanking pulse
- field-synchronizing pulse
- firing pulse
- flat-topped pulse
- frame pulse
- frame-synchronizing pulse
- front-porch pulse
- fruit pulse
- gate pulse
- gating pulse
- Gaussian pulse
- ghost pulse
- giant laser pulse
- giant laser-emission pulse
- half-drive pulse
- half-select pulse
- horizontal blanking pulse
- horizontal-retrace blanking pulse
- horizontal-synchronizing pulse
- ignition pulse
- inhibit pulse
- initiating pulse
- input pulse
- insert pulse
- intensification pulse - inverted pulse
- key pulse
- killer pulse
- linear FM pulse
- line blanking pulse
- line-frequency blanking pulse
- line-synchronizing pulse
- lockout pulse
- long pulse
- make pulse
- mark pulse
- marker pulse
- marking pulse
- microwave pulse
- nanosecond pulse
- narrow pulse
- noise pulse
- Nyquist pulse
- output pulse
- overflow pulse
- partial-drive pulse
- partial-read pulse
- partial-reading pulse
- partial-select pulse
- partial-write pulse
- phasing pulse
- picosecond pulse
- picture-synchronizing pulse
- postwrite disturb pulse
- preread disturb pulse
- priming pulse
- pump pulse
- pumping pulse
- punch pulse
- Q-switched pulse
- quench pulse
- radio pulse
- radio-frequency pulse
- raised cosine pulse
- read pulse
- reading pulse
- rectangular pulse
- reference frame pulse
- reply pulse
- returning-to-zero pulse
- RTZ pulse
- sample pulse
- sampling pulse
- sawtooth pulse
- select pulse
- selector pulse
- SFQ pulse
- sharp pulse
- sine pulse
- single flux quantum pulse
- single-polarity pulses
- solitary-wave pulse
- sonic pulse
- space pulse
- spontaneous laser pulse
- spurious pulse
- start pulse
- starting pulse
- steady-state pulse
- stop pulse
- strobe pulse
- stuffed pulse
- subtract pulse
- suppression pulse
- sync pulse
- synchronizing pulse
- tach pulse
- tail pulse
- tape video frame pulse
- timed pulse
- timing pulse
- tone-wheel pulse
- trailing pulse
- trapezoidal pulse
- triangular pulse
- trigger pulse
- triggering pulse
- ultrasonic pulse
- unidirectional pulses
- unipolar pulses
- unit pulse
- variable-duration pulse
- vertical blanking pulse
- vertical-retrace blanking pulse
- vertical-synchronizing pulse
- video pulse
- write pulse

- acoustic relay
- active-power relay
- add-and-subtract relay
- alarm relay
- Allström relay
- all-to-all relay
- annunciation relay
- antenna relay
- antiplugging relay
- armature relay
- auxiliary relay
- balanced relay
- baseband relay
- biased relay
- bistable relay
- blocking relay
- break-in relay
- calling relay
- capacitance relay
- center-stable polar relay
- clapper relay
- clearing relay
- close-differential relay
- closing relay
- coaxial relay
- code relay
- command relay
- compelled relay
- conductance relay
- connector relay
- contact relay
- contactless relay
- continuous duty relay
- control relay
- correed relay
- current relay
- dc relay
- definite-purpose relay
- delay relay
- diaphragm relay
- differential relay
- digital radio relay
- direct-action relay
- directional relay
- directional-current relay
- directional-overcurrent relay
- directional-polarity relay
- directional-power relay
- directional-resistance relay
- directional-voltage relay
- directivity relay
- distance relay
- dry-reed relay
- earth-fault relay
- electrical relay
- electrical-mechanical relay
- electromagnetic relay
- electromechanical relay
- electronic relay
- electronic-tube relay
- electrostatic relay
- electrostrictive relay
- enclosed relay
- extraterrestrial relay
- fast-operate relay
- fast-packet frame-relay
- fast-release relay
- fault selective relay
- ferrodynamicrelay
- field application relay
- field loss relay
- flat-type relay
- flow relay
- frequency relay
- frequency-selective relay
- frequency-sensitive relay
- gas-filled relay
- gas-filled reed relay
- general-purpose relay
- ground relay
- ground protective relay
- group-selector relay
- guard relay
- heavy-duty relay
- hermetically sealed relay
- high G-relay
- high-speed relay
- homing relay
- hot-wire relay
- impedance relay
- indicating relay
- indirect-action relay
- inertia relay
- initiating relay
- instantaneous overcurrent relay
- instrument-type relay
- integrating relay
- interlock relay
- intersatellite relay
- key relay
- Kipp relay
- lag relay
- latch-in relay
- latching relay
- LED-coupled solid-state relay
- light relay
- light-activated switching relay
- line relay
- line-break relay
- locking relay
- lockout relay
- lock-up relay
- logic relay
- magnetic reed relay
- magnetostrictive relay
- manual-automatic relay
- marginal relay
- mechanical locking relay
- memory relay
- mercury relay
- mercury-contact relay
- mercury-wetted reed relay
- metering relay
- meter-type relay
- mho relay
- microwave relay
- microwave-radio relay
- motor-field failure relay
- multiposition relay
- NC relay
- net-to-net relay
- network relay
- network master relay
- network phasing relay
- neutral relay
- NO relay
- nonpolarized relay
- normally-closed relay
- normally-open relay
- notching relay
- open relay
- open-phase relay
- oscillating relay
- overcurrent relay
- overfrequency relay
- overload relay
- overpower relay
- overvoltage relay
- percentage-differential relay
- phase-balance relay
- phase-reversal relay
- phase-rotation relay
- phase-sequence relay
- phase-shift relay
- photoelectric relay
- plunger relay
- polar relay
- polarized relay
- polyphase relay
- power relay
- pressure relay
- protective relay
- pulse reed relay
- radar relay
- radio relay
- ratchet relay
- rate-of-change relay
- rate-of-change temperature relay
- rate-of-rise relay
- ratio-balance relay
- ratio-differential relay
- reactance relay
- reactive-power relay
- reclosing relay
- reed relay
- register relay
- regulating relay
- remanent relay
- reset relay
- residual relay
- resistance relay
- resonant-reed relay
- reverse relay
- reverse-current relay
- ringing relay
- rotary stepping relay
- satellite relay
- selector relay
- self-latching relay
- semiconductor relay
- sensitive relay
- separating relay
- sequence relay
- sequential relay
- side-stable relay
- signal-actuated relay
- single-phase relay
- slave relay
- slow-acting relay
- slow-action relay
- slow-cutting relay
- slow-operate relay
- slow-release relay
- solenoid relay
- solid-state relay
- space relay
- speed-sensitive relay
- spring-actuated stepping relay
- SR relay
- stepping relay
- storage relay
- supersensitive relay
- surge relay
- synchronizing relay
- tape relay
- temperature relay
- test relay
- thermal relay
- thermostat relay
- three-position relay
- three-step relay
- time relay
- time-delay relay
- timing relay
- transformer-coupled solid-state relay
- transhorizon radio relay
- trip-free relay
- tripping relay
- trunk relay
- tuned relay
- two-position relay
- two-step relay
- undercurrent relay
- underfrequency relay
- underpower relay
- undervoltage relay
- vacuum reed relay
- valve relay
- vibrating relay
- voltage relay
- zero phase-sequence relay