International

Electrotechnical

Commission

Area: 721: Telegraphy, facsimile and data communication Index language:

Section 721-01: Forms of telecommunications using discrete signals
	721-01-01	teleprocessing
	721-01-02	data
	721-01-03	data communication
	721-01-04	data transmission
	721-01-05	telematics (services)
	721-01-06	telegraphy
	721-01-07	alphabetic telegraphy
	721-01-08	telewriting
	721-01-09	facsimile
	721-01-10	document facsimile
	721-01-11	picture facsimile
	721-01-12	phototelecopy
	721-01-13	telegraph service
	721-01-14	telegram service
	721-01-15	telex (service)
	721-01-16	supertelex (service)
	721-01-17	teletex (service)
Section 721-02: Discretely-timed and digital signals, signal elements
	721-02-01	discretely-timed signal
	721-02-02	digital signal
	721-02-03	analogue signal
	721-02-04	sampling (of a signal)
	721-02-05	quantization
	721-02-06	signal element
	721-02-07	digit
	721-02-08	binary digit
	721-02-09	binary figure
	721-02-10	n-ary digit
	721-02-11	n-bit byte (1)
	721-02-12	doublet
	721-02-13	triplet
	721-02-14	quartet (byte)
	721-02-15	quintet (byte)
	721-02-16	sextet (byte)
	721-02-17	septet (byte)
	721-02-18	byte
	721-02-19	n-bit byte (2)
	721-02-20	code
	721-02-21	code conversion
	721-02-22	significant condition
	721-02-23	number of significant conditions
	721-02-24	two conditions
	721-02-25	three conditions
	721-02-26	four conditions
	721-02-27	change-over
	721-02-28	transition
	721-02-29	significant instant
	721-02-30	significant interval
	721-02-31	theoretical duration of a significant interval
	721-02-32	unit interval
	721-02-33	unit element
Section 721-03: Transmission using discretely-timed or digital signals
	721-03-01	isochronous, adj
	721-03-02	anisochronous, adj
	721-03-03	start-stop signal
	721-03-04	synchronous
	721-03-05	synchronous transmission
	721-03-06	anisochronous transmission
	721-03-07	start-stop transmission
	721-03-08	digital transmission (of a discretely-timed signal)
	721-03-09	character
	721-03-10	character signal
	721-03-11	block
	721-03-12	start-of-block signal
	721-03-13	end-of-block signal
	721-03-14	block signal
	721-03-15	start signal
	721-03-16	start element
	721-03-17	stop signal
	721-03-18	stop element
	721-03-19	A condition
	721-03-20	Z condition
	721-03-21	equal length code
	721-03-22	n-unit code
	721-03-23	code word
	721-03-24	A element
	721-03-25	Z element
	721-03-26	modulation rate
	721-03-27	baud
	721-03-28	speed conversion
	721-03-29	actual transfer rate
	721-03-30	binary rate
	721-03-31	effective transfer rate
Section 721-04: Transmission channels and methods
	721-04-01	telephone-type channel
	721-04-02	telephone-type circuit
	721-04-03	wideband channel
	721-04-04	multiplex
	721-04-05	multiplexing
	721-04-06	demultiplexing
	721-04-07	multiplexer
	721-04-08	demultiplexer
	721-04-09	muldex
	721-04-10	multiplex signal
	721-04-11	time division multiplexing
	721-04-12	frequency division multiplexing
	721-04-13	homogeneous multiplex
	721-04-14	heterogeneous multiplex
	721-04-15	simplex, adj and noun
	721-04-16	duplex, adj and noun
	721-04-17	differential duplex, adj and noun
	721-04-18	bridge duplex, adj and noun
	721-04-19	incremental duplex
	721-04-20	opposition duplex
	721-04-21	unidirectional, adj
	721-04-22	bidirectional
	721-04-23	one-way, adj
	721-04-24	both-way, adj
	721-04-25	(frequency) channel
	721-04-171	differential duplex, adj
	721-04-172	differential duplex, noun
	721-04-181	bridge duplex, adj
	721-04-182	bridge duplex, noun
Section 721-05: Direct current transmission
	721-05-01	direct current transmission
	721-05-02	single current transmission
	721-05-03	double current transmission
	721-05-04	on-off transmission
	721-05-05	sub-telephone transmission
	721-05-06	phantom circuit
	721-05-07	earth-return phantom circuit
	721-05-08	earth-return double phantom circuit
	721-05-09	double phantom circuit
	721-05-10	Desieter telegraph translation
Section 721-06: Carrier transmission, multiplexing
	721-06-01	carrier transmission
	721-06-02	time division multiplex transmission
	721-06-03	differential modulation, <in telegraphy>
	721-06-04	modulation with a fixed reference
	721-06-05	amplitude shift keying
	721-06-06	frequency shift keying
	721-06-07	phase shift keying
	721-06-08	differential phase shift keying
	721-06-09	phase inversion modulation
	721-06-10	quadrature phase shift keying
	721-06-11	modulation index, <in two-condition frequency shift keying>
	721-06-12	coherent modulation
	721-06-13	super-telephone transmission
	721-06-14	interband transmission
	721-06-15	intraband transmission
	721-06-16	speech + simplex (equipment)
	721-06-17	speech + duplex (equipment)
	721-06-18	bisector
	721-06-19	first data multiplexer
	721-06-20	second data multiplexer
	721-06-21	frame, <in time division multiplexing>
	721-06-22	sub-frame
	721-06-23	frame alignment
	721-06-24	frame alignment recovery time
Section 721-07: Transmission performance, distortion in time
	721-07-01	perfect (discrete) signal
	721-07-02	ideal instant
	721-07-03	time distortion
	721-07-04	incorrect (discrete) signal
	721-07-05	degree of individual distortion (of a particular significant instant)
	721-07-06	degree of isochronous distortion
	721-07-07	degree of start-stop distortion
	721-07-08	degree of gross start-stop distortion
	721-07-09	degree of synchronous start-stop distortion
	721-07-10	degree of standardized test distortion
	721-07-11	inherent distortion (of a transmission channel)
	721-07-12	bias distortion
	721-07-13	degree of bias distortion
	721-07-14	characteristic distortion
	721-07-15	fortuitous distortion
	721-07-16	cyclic distortion
	721-07-17	conventional degree of distortion
	721-07-18	teledistortion
	721-07-19	transmitter distortion
	721-07-20	degree of early anisochronous parallel distortion
	721-07-21	degree of late anisochronous parallel distortion
	721-07-22	margin (of a receiver or other terminal)
	721-07-23	net margin
	721-07-24	effective margin (of a given apparatus)
	721-07-25	nominal margin (of a type of apparatus)
	721-07-26	theoretical margin
	721-07-27	margin (of a start-stop apparatus)
	721-07-28	synchronous (start-stop) margin
	721-07-29	margin of a synchronous receiver
Section 721-08: Errors and error control
	721-08-01	mutilation
	721-08-02	erroneous digit
	721-08-03	erroneous binary digit
	721-08-04	erroneous character
	721-08-05	erroneous block
	721-08-06	single error
	721-08-07	double error
	721-08-08	triple error
	721-08-09	error burst
	721-08-10	error burst length
	721-08-11	digit error ratio
	721-08-12	character error ratio
	721-08-13	block error ratio
	721-08-14	error control
	721-08-15	block check
	721-08-16	error detection
	721-08-17	error detection without repetition
	721-08-18	loop checking
	721-08-19	echoplex
	721-08-20	error correction
	721-08-21	error detecting and feedback system
	721-08-22	error correction by information feedback and repetition
	721-08-23	redundant code
	721-08-24	code word
	721-08-25	Hamming distance
	721-08-26	error protection code
	721-08-27	error detecting code
	721-08-28	error correcting code
	721-08-29	constant ratio code
	721-08-30	Van Duuren code
	721-08-31	cyclic code
	721-08-32	contention
	721-08-33	recovery procedure
	721-08-34	efficiency factor in time (of a transmission with automatic repetition for the correction of errors)
	721-08-35	signal repetition
	721-08-36	repetition cycle
	721-08-37	RQ cycle
	721-08-38	BQ cycle
	721-08-39	non-print cycle
	721-08-40	gated RQ
	721-08-41	tested RQ
	721-08-42	testing repetition cycle
	721-08-43	pre-correction
	721-08-44	information bit
	721-08-45	service digit
	721-08-46	check bit
	721-08-47	character check
	721-08-48	block check
	721-08-49	check digit
	721-08-50	even parity check
	721-08-51	odd parity check
	721-08-52	parity code
	721-08-53	parity digit
	721-08-54	automatic repetition Verdan system
	721-08-55	(signal) quality detection
	721-08-56	residual error-rate
	721-08-57	information security
Section 721-09: Codes and alphabets
	721-09-01	message (in telegraphy and data communication)
	721-09-02	packet
	721-09-03	telegraph signal
	721-09-04	data signal
	721-09-05	telegraph code
	721-09-06	data code
	721-09-07	(telegraph) alphabet
	721-09-08	n-unit code alphabet
	721-09-09	International Telegraph Alphabet No. 1
	721-09-10	International Telegraph Alphabet No. 2
	721-09-11	International Telegraph Alphabet No. 3
	721-09-12	International Telegraph Alphabet No. 4
	721-09-13	International Alphabet No. 5
	721-09-14	telegraph modulation
	721-09-15	restitution
	721-09-16	isochronous modulation
	721-09-17	synchronous telegraphy
	721-09-18	synchronous data transmission
	721-09-19	start-stop system of telegraphy
	721-09-20	start-stop system of data transmission
	721-09-21	stepped start-stop system of telegraphy
	721-09-22	stepped start-stop system of data transmission
	721-09-23	Morse telegraphy
	721-09-24	Wheatstone automatic system
	721-09-25	Morse code
	721-09-26	mark condition (in Morse code)
	721-09-27	space condition (in Morse code)
	721-09-28	dot (in Morse code)
	721-09-29	dash (in Morse code)
	721-09-30	space (between characters and words in Morse code)
Section 721-10: Function controls and function signals
	721-10-01	function control
	721-10-02	function signal
	721-10-03	control character
	721-10-04	translation (in telegraphy and data transmission)
	721-10-05	selection (in a telegraph receiver)
	721-10-06	local record
	721-10-07	format effector
	721-10-08	line feed
	721-10-09	carriage return
	721-10-10	case shift
	721-10-11	letters case
	721-10-12	letters shift
	721-10-13	letter-shift signal
	721-10-14	figures case
	721-10-15	figures shift
	721-10-16	figure-shift signal
	721-10-17	space signal
	721-10-18	letters shift-on space
	721-10-19	erasure signal
	721-10-20	"Who are you" signal (function)
	721-10-21	answer-back code
	721-10-22	synchronisation control
	721-10-23	start-of-heading signal
	721-10-24	start-of-text signal
	721-10-25	end-of-text signal
	721-10-26	end-of-transmission signal
	721-10-27	transmission control (function)
	721-10-28	identification request
	721-10-29	acknowledge
	721-10-30	negative acknowledge
	721-10-31	form feed
	721-10-32	horizontal tabulation
	721-10-33	vertical tabulation
	721-10-34	backspace
	721-10-35	device control
	721-10-36	cancellation control
	721-10-37	substitute character
	721-10-38	null character
	721-10-39	stuffing character
	721-10-40	warning signal
	721-10-41	end-of-medium signal
	721-10-42	escape
	721-10-43	code shift
	721-10-44	code reversion
	721-10-45	information separator
	721-10-46	reversals
	721-10-47	switching signal telex-data
	721-10-48	call control character
	721-10-49	facility request signal
	721-10-50	request data transfer
Section 721-11: Transmission channels and processes
	721-11-01	telegraph channel
	721-11-02	data channel
	721-11-03	complete telegraph channel
	721-11-04	telegraph circuit
	721-11-05	data circuit
	721-11-06	forward channel
	721-11-07	backward channel
	721-11-08	status channel
	721-11-09	transmit channel
	721-11-10	return channel
	721-11-11	telegraph repeater
	721-11-12	telegraph regenerative repeater
	721-11-13	modulation converter
	721-11-14	hypothetical reference connection (in telegraphy)
	721-11-15	nominated reserved circuit
	721-11-16	serial transmission
	721-11-17	parallel transmission
	721-11-18	coherent significant instants
	721-11-19	character-serial transmission
	721-11-20	byte-serial transmission
	721-11-21	multi-channel
	721-11-22	voice-frequency multiplex telegraphy
	721-11-23	set of voice-frequency multiplex (telegraph) circuits
	721-11-24	burst isochronous
	721-11-25	quadruplex system
	721-11-26	telegraph multiplex
	721-11-27	character interleaved telegraphy
	721-11-28	bit-interleaved telegraphy
	721-11-29	Baudot telegraphy
	721-11-30	Van Duuren radiotelegraph system
	721-11-31	frequency shift telegraphy
	721-11-32	four-frequency duplex telegraphy
	721-11-33	signal recording telegraphy
	721-11-34	in-local
	721-11-35	automatic retransmission
	721-11-36	printing telegraphy
	721-11-37	mosaic telegraphy
	721-11-38	Hell system
	721-11-39	aggregate (isochronous) signal
	721-11-40	balanced aggregate signal
	721-11-41	multiplex aggregate bit rate
	721-11-42	character cycle
	721-11-43	element synchronism
	721-11-44	element synchronization
	721-11-45	synchronization bit
	721-11-46	synchronous correction
	721-11-47	correction signal
	721-11-48	correction from signals
	721-11-49	phase relationship, <in synchronous transmission>
	721-11-50	character in phase
	721-11-51	sub-channel
	721-11-52	sub-channel phase transmission
	721-11-53	orientation
	721-11-54	orientation range
	721-11-55	sector
	721-11-56	idle circuit condition
	721-11-57	inter-character rest condition
Section 721-12: Telegraph and data transmission equipments
	721-12-01	subscriber's installation
	721-12-02	(telegraph) terminal
	721-12-03	data terminal equipment
	721-12-04	packet mode terminal
	721-12-05	data circuit terminating equipment
	721-12-06	network termination unit
	721-12-07	data station
	721-12-08	data source
	721-12-09	data sink
	721-12-10	modem
	721-12-11	interface
	721-12-12	interface (specification)
	721-12-13	telewriter (1)
	721-12-14	start-stop apparatus
	721-12-15	teleprinter
	721-12-16	page teleprinter
	721-12-17	tape teleprinter
	721-12-18	alphanumeric keyboard
	721-12-19	motorized keyboard
	721-12-20	saw-tooth keyboard
	721-12-21	storage keyboard
	721-12-22	tape-reading head
	721-12-23	(teleprinter) control unit
	721-12-24	direct printer
	721-12-25	(tape) perforator
	721-12-26	keyboard perforator
	721-12-27	printing perforator
	721-12-28	reperforator
	721-12-29	printing reperforator
	721-12-30	centre holes
	721-12-31	chadless perforation
	721-12-32	track
	721-12-33	telegraph transmitter
	721-12-34	keyboard transmitter
	721-12-35	automatic transmitter
	721-12-36	automatic numbering transmitter
	721-12-37	automatic retransmitter
	721-12-38	perforated-tape retransmitter
	721-12-39	coupled reperforator and tape reader
	721-12-40	automatic transmitter with controlled tape-feed mechanism
	721-12-41	answer-back unit
	721-12-42	answer-back unit simulator
	721-12-43	tape printer
	721-12-44	Morse key
	721-12-45	sounder
	721-12-46	Morse undulator
	721-12-47	siphon recorder
	721-12-48	duplex apparatus
	721-12-49	half-duplex apparatus
	721-12-50	telegraph relay
	721-12-51	vibrating relay (telegraph)
	721-12-52	code converter
	721-12-53	telegraph modulator
	721-12-54	telegraph demodulator
	721-12-55	telegraph discriminator
	721-12-56	radiotelegraph converter
	721-12-57	shift register
	721-12-58	acoustic coupling (to a telephone line)
	721-12-59	acoustic coupler (for data transmission)
Section 721-13: Facsimile equipments and services
	721-13-01	document facsimile equipment, Group 1
	721-13-02	document facsimile equipment, Group 2
	721-13-03	document facsimile equipment, Group 3
	721-13-04	drum facsimile transmitter
	721-13-05	flat bed facsimile transmitter
	721-13-06	drum facsimile receiver
	721-13-07	continuous facsimile receiver
	721-13-08	telewriter (2)
	721-13-09	telefax
	721-13-10	datafax
	721-13-11	bureaufax
Section 721-14: Facsimile operational characteristics
	721-14-01	scanning (in facsimile transmitter)
	721-14-02	scanning (in facsimile receiver)
	721-14-03	scanning spot (at transmission)
	721-14-04	scanning spot (at reception)
	721-14-05	scanning field
	721-14-06	scanning line
	721-14-07	scanning line period
	721-14-08	scanning line frequency
	721-14-09	aspect ratio
	721-14-10	picture element
	721-14-11	longitudinal resolution (of a facsimile transmitter)
	721-14-12	transverse resolution (of a facsimile transmitter)
	721-14-13	longitudinal resolution (of a facsimile receiver)
	721-14-14	transverse resolution (of a facsimile receiver)
	721-14-15	dot frequency
	721-14-16	phasing (in facsimile)
	721-14-17	phasing signal
	721-14-18	phasing on white
	721-14-19	phasing on black
	721-14-20	synchronization (in facsimile)
	721-14-21	aperture (of a facsimile transmitter)
	721-14-22	aperture (of a facsimile receiver)
	721-14-23	dead sector
	721-14-24	lost time
	721-14-25	writing helix
	721-14-26	writing bar
	721-14-27	drum factor
	721-14-28	scanning pitch
	721-14-29	scanning density
	721-14-30	scanning speed
	721-14-31	usable scanning line length
	721-14-32	total scanning line length
	721-14-33	factor of cooperation
	721-14-34	index of cooperation
	721-14-35	limited scanning
	721-14-36	reproduction ratio
	721-14-37	positive scanning shift
	721-14-38	negative scanning shift
	721-14-39	maximum contrast
	721-14-40	compression of the luminance range
	721-14-41	expansion of the luminance range
	721-14-42	luminance compensation
	721-14-43	nominal black
	721-14-44	nominal white
	721-14-45	accentuated contrast
	721-14-46	picture black
	721-14-47	picture white
	721-14-48	tone control aperture
	721-14-49	half tone picture
	721-14-50	tone wedge
Section 721-15: Defects and distortion in facsimile reproduction
	721-15-01	aperture distortion
	721-15-02	tailing
	721-15-03	echo effect
	721-15-04	interference pattern (in facsimile)
	721-15-05	longitudinal judder
	721-15-06	transverse judder
	721-15-07	noisy blacks
	721-15-08	overlap (in facsimile)
	721-15-09	underlap
	721-15-10	skew
	721-15-11	partial tone reversal
Section 721-16: Telegraph and data networks
	721-16-01	public telegram network
	721-16-02	gentex network
	721-16-03	subscriber's line
	721-16-04	local line
	721-16-05	dedicated circuit (in telegraphy and data transmission)
	721-16-06	international circuit
	721-16-07	intercontinental circuit
	721-16-08	set of circuits
	721-16-09	private network (in telegraphy and data transmission)
	721-16-10	overflow position
	721-16-11	closed private network
	721-16-12	interworking between networks
	721-16-13	data network
	721-16-14	synchronous data network
	721-16-15	time base
	721-16-16	timescale
	721-16-17	cyclic timescale
	721-16-18	public data network
	721-16-19	node, <in communication networks>
	721-16-20	branch (of a data network)
	721-16-21	path (of a data network)
	721-16-22	(terminal) port (of a network)
	721-16-23	data link
	721-16-24	circuit switched connection
	721-16-25	multipoint connection
	721-16-26	point-to-point connection
	721-16-27	virtual circuit
	721-16-28	permanent virtual circuit
	721-16-29	virtual call
	721-16-30	transparency (in telegraphy and data transmission)
	721-16-31	code independent
Section 721-17: Telegraph and data switching, signalling
	721-17-01	connection
	721-17-02	(complete) connection
	721-17-03	(telex) call
	721-17-04	subscriber serving exchange
	721-17-05	telegraph transit exchange
	721-17-06	telegraph switching exchange
	721-17-07	data switching exchange
	721-17-08	sub-centre
	721-17-09	line concentrator
	721-17-10	telegraph trunk circuit
	721-17-11	telegraph junction circuit
	721-17-12	overline service
	721-17-13	overflow (in telegraphy)
	721-17-14	circuit switching
	721-17-15	message switching
	721-17-16	packet switching
	721-17-17	reperforator switching
	721-17-18	character switching
	721-17-19	circuit switching exchange
	721-17-20	message switching exchange
	721-17-21	national subscriber's telex number
	721-17-22	local telex number
	721-17-23	short code selection
	721-17-24	short address
	721-17-25	call without selection signals
	721-17-26	follow-on-call
	721-17-27	selection error correction
	721-17-28	alternative selection signals
	721-17-29	prefix giving access to the long-distance telex network
	721-17-30	prefix giving access to the international telex network
	721-17-31	prefix giving access to the intercontinental telex network
	721-17-32	destination code
	721-17-33	international selection sequence
	721-17-34	international two-stage selection
	721-17-35	label (in signalling)
	721-17-36	traffic routing (in circuit switching)
	721-17-37	normal (traffic) routing
	721-17-38	alternative traffic routing
	721-17-39	first choice set of circuits
	721-17-40	emergency routing
	721-17-41	re-routing
	721-17-42	switching signal
	721-17-43	forward switching signal
	721-17-44	return switching signal
	721-17-45	free circuit condition
	721-17-46	ready
	721-17-47	not ready
	721-17-48	ready for data signal
	721-17-49	data channel signalling conditions
	721-17-50	calling signal
	721-17-51	call control procedure
	721-17-52	call-confirmation (signal)
	721-17-53	call accepted (signal)
	721-17-54	selection signals
	721-17-55	address (in circuit switching)
	721-17-56	address (in information processing)
	721-17-57	proceed-to-select signal
	721-17-58	(user) class of service signal
	721-17-59	pre-signal
	721-17-60	post-signal
	721-17-61	end-of-selection signal
	721-17-62	keyboard selection
	721-17-63	dial selection (in telegraphy switching)
	721-17-64	call-connected signal
	721-17-65	clearing signal
	721-17-66	confirmation of clearing signal
	721-17-67	service signal
	721-17-68	engaged signal
	721-17-69	barred signal
	721-17-70	call set-up time
	721-17-71	preselection delay
	721-17-72	selection time
	721-17-73	post-selection time
	721-17-74	effective duration of a call
	721-17-75	stored program control
	721-17-76	common channel signalling
	721-17-77	channel associated signalling
	721-17-78	call clearing delay
	721-17-79	unsuccessful call
	721-17-80	call not accepted signal
	721-17-81	lost call
	721-17-82	head on collision
	721-17-83	terminal connection method (in telex)
	721-17-84	speed converter concentrator
	721-17-85	data concentrator
	721-17-86	system control station
Section 721-18: Telegraph operation and services
	721-18-01	telegram
	721-18-02	document facsimile telegram
	721-18-03	photograph facsimile telegram
	721-18-04	radiotelegram
	721-18-05	telex conversation mode
	721-18-06	radiotelex call
	721-18-07	access to the public telegram network
	721-18-08	user class of service
	721-18-09	public telex booth
	721-18-10	outgoing only terminal
	721-18-11	incoming only terminal
	721-18-12	access barred
	721-18-13	restricted service
	721-18-14	priority
	721-18-15	absolute priority
	721-18-16	priority for called subscriber
	721-18-17	in local override
	721-18-18	direct outgoing selection
	721-18-19	direct incoming selection
	721-18-20	direct incoming selection with integrated numbering
	721-18-21	direct incoming selection with two-stage selection
	721-18-22	closed user group
	721-18-23	partially closed user group
	721-18-24	interlock code
	721-18-25	user facility
	721-18-26	automatic calling
	721-18-27	automatic answering
	721-18-28	manual answering
	721-18-29	automatic identification
	721-18-30	line identification by the network
	721-18-31	automatic date and time indication
	721-18-32	indication of duration
	721-18-33	indication of charge
	721-18-34	statement of call account
	721-18-35	shared terminal
	721-18-36	accounts for shared terminal
	721-18-37	storage of call content
	721-18-38	retrieval of stored call content
	721-18-39	statistics on request
	721-18-40	recorded message
	721-18-41	camp-on
	721-18-42	camp-on with recall
	721-18-43	absent subscriber service (in telegraphy and data communication)
	721-18-44	call redirection
	721-18-45	changed address interception
	721-18-46	store-and-forward
	721-18-47	storage installation
	721-18-48	redirection address
	721-18-49	delayed delivery
	721-18-50	message priority
	721-18-51	message spacing
	721-18-52	header
	721-18-53	booked call
	721-18-54	network recall
	721-18-55	multi-address call
	721-18-56	conference call
	721-18-57	broadcast call
	721-18-58	restricted conference call
	721-18-59	broadcast conference call
	721-18-60	group call (in a maritime mobile service)
	721-18-61	automatic sequential connection
	721-18-62	delivery confirmation
	721-18-63	telecommunication security
	721-18-64	data collection
Section 721-19: Data transmission operation and services
	721-19-01	link protocol
	721-19-02	burst transmission
	721-19-03	calling (in data communication)
	721-19-04	manual calling (in data communication)
	721-19-05	answering (in data communication)
	721-19-06	interrogation
	721-19-07	polling
	721-19-08	selecting
	721-19-09	packet sequencing
	721-19-10	control station
	721-19-11	tributary station
	721-19-12	master station
	721-19-13	slave station
	721-19-14	passive station
	721-19-15	primary station
	721-19-16	secondary station
	721-19-17	combined station
	721-19-18	routing (in packet switched data communication)
	721-19-19	adaptative routing
	721-19-20	packet assembly
	721-19-21	packet disassembly
	721-19-22	packet format
	721-19-23	datagram service
	721-19-24	aligner
	721-19-25	envelope
	721-19-26	permanently locked envelopes
	721-19-27	data transfer phase
	721-19-28	network control phase
	721-19-29	transfer time
	721-19-30	flow control
	721-19-31	transmit flow control
	721-19-32	adaptative channel allocation