Glossary for Interactive TV
Advanced Application Platform specified by ATSC. ACAP is based on the
GEM and DASE standards and includes some additional functionality from
Advertising spots available to a cable operator to insert local advertising
on a cable network.
Application Information Table. Provides information about the activation
state of bound OCAP applications.
ATSC Link-layer Protocol, as defined in A/330.
ALP provides link layer signaling consisting of a header, links, and payloads. The link layer protocol isolates
various transport types from the Physical (Transmission) Layer.
ALP allows broadcasters to perform IP and TS packet encapsulation, segmentation and reassembly, concatenation,
and header compression within this layer. The Link Mapping Table (LMT) is included in the ALP layer. The LMT provides a
list of multicasts carried in a PLP. The LMT also provides additional information for processing the ALP packets
carrying the multicasts in the link layer.
A process of transmitting radio frequency signals by varying the amplitude.
This process is used for radio, television and fax.
American National Standards Institute - a standards body of the United States.
Application Protocol Data Unit.
A common structure to send application data between CableCARD and the
Application Programming Interface.
Association of Radio Industries and Businesses. Japanese iTV middleware
ATCaster is an ATSC 3.0 broadcast stream generator
written by S&T and sold by UniSoft. ATCaster is offered either individually or as part of
UniSoft's ATSC 3.0 delivery system.
Automatic Testing Environment. This is a server and software architecture
used by CableLabs and other organisations for the delivery of conformance
tests to receivers under test ("RUTs").
Advanced Television Systems Committee formed to establish a set of technical
standards for broadcasting in High Definition (HDTV). UniSoft is currently
a member of ATSC.
The ATSC Signature File Generator. A UniSoft provided product that will sign
ATSC 3.0 signaling and applications as required by the A/360 specification.
is integrated with S&T's
broadcast stream generator.
Bandwidth: The data rate of a digital signal which is commonly stated
in units of bits-per-second (bps).
Applications (OCAP and MHP usually) which are associated with a particular
TV channel (service). When the viewer changes channel, the application
bound to the previous channel is terminated.
A stream of packets sent from a CMTS to a cable modem embedded in
a set-top-box or receiver.
Removable security card for digital cable terminals, as defined by the
Certification Data Table.
The A/360 specification defines a new LLS table that carries X.509 Certificates and OCSP responses
that are used to verify signed ATSC 3.0 Signaling Messages.
The Certification Data LLS table has the LLS_table_id 0x06.
A digitally signed file containing the public key used in digital signature
verification and details of the owner and issuer of that public key.
Campaign Information Package Interface.
The CIP is a component of
which is used to inform all MSO systems that have a direct role in the
preparation, delivery, execution, or reporting of the interactive campaign
Cable Modem Termination System. A router which interfaces between Ethernet
networks and RF network connections to cable modems.
OpenCable Content Definition Format. This CableLabs' specification defines
a standard format in which ETV and OCAP applications may be distributed amongst
application authors, application playout systems and a variety of
content delivery systems.
CoDF files are written in XML and describe the various components that
may comprise a simple to complex application. Components can be application
resources, data, or signaling. The CoDF syntax includes instructions
for how to integrate an application, data and signals into a stream, with
or without a video/audio component.
A protocol for OpenCable-certified hosts for the purpose of updating
any of the firmware objects used in the host device.
Code Verification Certificate. This is a X509 certificate issued by
a Cablelabs' approved Certificate Authority (typically the CableLabs CVC CA)
and used for signature of code images or CVTs.
Code Version Table. A message used to indicate the availability of a code
image download when signaled to the eSTB component of a Host device.
Digital Access Controller. Cable headend control system from Motorola used by
many of the US MSOs and cable operators.
Downstream Channel Descriptor.
A DSG address table used within the DOCSIS MAC Management Message to manage
the DSG Tunnel. DCDs sent out by a CMTS can be detected by an OCAP receiver and
provide the receiver with sufficient information to receive data from
the DSG tunnel. XAITs can be transmitted down DSG broadcast tunnels.
Digital Consumer Terminal. Digtial cable set-top-boxes
manfactured by Motorola and used by many US cable companies.
Some DCT models, such as the DCT2000, can support both analog and
digital signals. Digital transmission can be either QAM 64 or QAM 256
A data structure used in MPEG encoding which consists of
tag, length and value (TLV) fields. Private descriptors may also be defined
where the data portion (value) of these descriptors is privately defined.
A message digest is a one way function that generates a statistically unique
sample for a set of input data.
DigiCipher II, DigiCipher 2, or DCII, is a proprietary standard
format of digital signal transmission and encryption with MPEG-2
video compression. The DCII standard was originally developed in 1997
by General Instrument, which is now the Home and Network Mobility
division of Motorola. The use of DCII is most prevalent in
North American digital cable television set top boxes.
Designated Market Area.
With respects to TV advertising, DMAs provide a way of designating particular
geographic markets and are often ranked by the size of population.
Digital Network Control System, a product of Cisco (formerly Scientific-Atlanta, Inc.).
The Digital Broadband Delivery System (DBDS)
receives analog and digital services from a variety of sources including
satelitte and securely transports the services to the subscribers home.
Services supported by the DBDS are controlled by the DNCS.
DOCSIS Set-Top Gateway.
DSG Address Table
The collection of DSG Rules and DSG Classifiers contained within the DCD
Digital Storage Media Command and Control. A format for transmission
of data and control information in an MPEG-2 Private Section,
defined by Part 6 of the ISO/IEC 13818 MPEG-2 standard.
Applications of which include data and object carousels. These data
structures are used to transmit EBIF and OCAP applications respectively.
Digital Transport Adapter, a unit which converts digital standard definition
TV signals to analogue NTSC allowing cable operators to transition to
all-digital broadcasting - the DTA provides a solution for the analogue
subscribers. Transistion to all digital allows the operator to
reallocate analogue bandwidth for the deployment of many High Definition
Digital Video Broadcasting program within the European Broadcasting
Union (EBU). DVB specified the MHP middleware standard.
Emergency Alert Signaling method for cable TV.
This is a standard which defines an Emergency Alert signaling method for
use by cable TV systems to signal emergencies to digital set-top-boxes.
ETV Binary Interchange Format. The binary format used to encode
ETV Integrated Signaling Stream - an MPEG elementary stream which carries
media timeline messages, stream events and EISS tables for an ETV application.
Enhanced Television, a specification by CableLabs which allows deployment
of interactive content on "thin-clients" such as the Motorola DCT 2000
(with over 15M platforms deployed) and Scientific Atlanta Explorer 2000
as well as OpenCable (OCAP) host devices.
The European Telecommunications Standards Institute, a recognized standards
body located in Southern France.
File Delivery over Unidirectional Transport. Used for file delivery of ATSC NRT content.
FLUTE is a protocol for delivery of arbitrary types of files
over a unidirectional IP link. It uses the IETF ALC (Asynchronous Layered Coding) protocol,
which in turn uses the IETF LCT (Layered Coding Transport) protocol.
The direction of radio frequency (RF) signal flow away from the headend
toward the end user; equivalent to downstream.
Globally Executable MHP. A terminal specification based on MHP that enables
applications to interoperate across OCAP, MHP and other GEM based platforms.
The control centre of a cable television system, where
incoming signals are amplified, converted, processed, and combined into a
common cable, along with any origination cable-casting, for transmission to
HTML Entry pages Location Description. A fragment of ATSC 3.0 Service Layer Signaling which
provides application-related metadata that enables the loading and unloading of an
ATSC 3.0 interactive application.
Set-top-box or receiver containing and executing the OpenCable Application
Platform implementation. It is also host to the CableCARD device.
Interactive Application Fulfillment Summary Interface is a component of
specification. The IAF provides a means for messaging generated by an
interactive application to be exposed to an external entity. Whilst individual
messages may flow over this interface, more typically a summary of messages
is transmitted, e.g., the aggregated results of a voting application.
Interactive Application Messaging (IAM) is a component of the
specifications. IAM defines the format and content of
of messages generated by interactive (EBIF) applications on a cable
receiver and transported to a network component within an MSO system.
Internet Media Subtitles and Captions Version 1. How subtitles are carried
in ATSC 3.0 as per the ATSC standard "Captions and Subtitles (A/343)".
Interactive TV usually means the viewer using the remote control to "interact"
with the TV to change the available video, audio and any graphics in some way.
These changes are typically made by an interactive software application
running in the set-top-box or TV.
Java Virtual Machine.
A public and private key pair. Information is encrypted using
a private key and others can use the corresponding public key to decrypt.
If decryption is successful, you have a high degree of confidence the
transmitted information originated from the registered holder of the private
With respects to SoftOC, Kit Files consist of transport packets and
DSM-CC modules plus an XML kit-control file. The control file describes
how to multiplex these parts at the section level in order to achieve
user defined MPEG /DVB/DSM-CC/OCAP table repetition rates.
Layer Division Multiplexing.
As defined in the physical layer specification, A/322, LDM is a constellation superposition technology that
PLPs at different power levels,
often with different modulation and channel coding schemes, prior to transmission in one RF channel.
Currently only two-layer LDM is used, a Core (or upper layer) and an Enhanced (or lower layer).
Generally use of LDM allows broadcasters to squeeze some additional bandwidth into their 6MHz channel.
Line 2238 Club
A delightful piece of UNIX folklore. A notion created by John Loins in
Chapter 8 of his publication in 1976 "A Commentary On The UNIX Operating System".
The commentary included the entire UNIX Version 6 source code and line 2238
is equivalent to line 325 of ken/slp.c; a comment in the C code which reads
"You are not expected to understand this.". Those that understand how V6 process
swapping works fully on a PDP 11 architecture are members of this club.
A link-local address is a network address that is valid only for communications within a network
segment (a single network link, or often: one broadcast domain) that a host is connected to.
Usually, link-local addresses are not guaranteed to be unique beyond a single network segment.
Routers therefore do not forward packets with link-local addresses.
Link-local addresses for IPv4 are defined in the address block 169.254.0.0/16. In IPv6, they are
assigned with the fe80::/64 prefix.
Multi-user operating system used by many OCAP receiver manufacturers
to execute their OCAP middleware implementations.
ATSC 3.0 Low Level Signaling. Delivered via multicast to 184.108.40.206 port 4937.
The LLS carries a number of table types including the Service List Table (SLT),
Rating Region Table (RRT), System Time Table (STT). Advanced Emergency Alert Table (AEAT)
and the On Screen Message Notication (OSMN) table.
S&T's broadcast stream generator,
, will generate LLS for ATSC 3.0.
Link Mapping Table. ATSC 3.0 signaling, LMT provides a list of multicasts carried in a
The LMT also provides additional information for processing the ALP packets carrying the
multicasts in the link layer.
Multimedia Home Platform specification produced by DVB.
In the context of interactive TV, the software which runs on a TV receiver
which is layer between the operating system and the applications. Most
middleware which are open standards are based on Java.
Multicast Listener Discovery Protocol. MLD is used by IPv6 routers for discovering multicast listeners
on a directly attached link, much like IGMP is used in IPv4. The protocol is embedded in ICMPv6
instead of using a separate protocol. MLDv1 is similar to IGMPv2 and MLDv2 similar to IGMPv3.
Man Machine Interface is another term for User Interface.
With respect to OCAP, MMI specifies the protocol used over the
CableCARD/host interface to enable the CableCARD device to display
messages on the television display.
MMT – MPEG Media Transport, ISO/IEC 23008-1. This an alternative to ROUTE for transmission
of ATSC 3.0 broadcast services over IP, where MMT protocol (MMTP) is used to deliver
Media Processing Units (MPU).
With respects to TSBroadcaster systems, a model means a snapshot
capture of a current TSBroadcaster configuration which is placed in a ZIP
file. The model includes all applications which have been registered
with TSBroadcaster, play-out schedules and configuration data. Models can
be uploaded to, and download from, a running TSBroadcaster system.
Modulation is the process of conveying a message signal, for example a
digital bit stream, inside another signal that can be physically
transmitted. For cable a plant, modulation is often to
for transmission over RF. Modulation Mode in the context of the
service information standard relates to a field of the
Longfrom Virtual Channel Table (LVCT) where the type of modulation
used is defined.
Moving Picture Experts Group. A group which develops standards for
digital, compressed moving pictures and associated audio.
MPEG-2 is a video compression standard commonly used by cable television
Multiple System Operator. A term for US cable companies that operate
multiple cable systems. Time Warner Cable and Comcast are MSOs.
MHP Test Consortium.
MHP Umbrella Group, which sets specifications for the Globally Executable MHP,
variations to the MHP specification to account for regional broadcast
A mechanism for failure recovery in computer architectures which consist
of multiple server systems. An additional server,
known as a "hot spare", is included which can act
as a replacement if any one of N systems fail.
Network Address Translation. NAT is the process of modifying IP address
information in IP packet headers whilst in transit across a traffic routing
The simplest type of NAT provides a one-to-one translation of IP addresses
and is known as "basic NAT" or "one-to-one NAT". NAT is often used for
IP address conservation. In this case it is common to hide an entire
IP address space, usually consisting of private IP addresses, behind a single
IP address (or in some cases a small group of IP addresses). To avoid
ambiguity in the handling of returned packets a one-to-many NAT must alter
higher level information such as TCP/UDP ports in outgoing communications and
must maintain a translation table so that return packets can be correctly
translated back. The terms NAPT (network address and port translation),
PAT (port address translation), IP masquerading, NAT Overload and
many-to-one NAT are used to describe this use case.
Typically an application which is written for the operating system of
a receiver (set-top-box) rather than the middleware standard that may
also be running on the receiver. ETV User Agents are implemented as
Network Information Table. The NIT is a
table carried in
PID 0x1FFC and present in SCTE-65. The NIT has a table_ID of 0xC2.
This table delivers sections of non-textual tables. The table types
included in the NIT are the Carrier Definition Subtable (CDS) and the
Modulation Mode Subtable (MMS).
Non-Real-Time. An ATSC standard defined in A/103 which refers to content
that is delivered in advance of its use and stored in the receiving device.
May refer to content that is delivered faster than real-time, such that
buffering is required in the receiving device.
Network Text Table. The NTT is a SCTE-65 Service Information table carried
in PID 0x1FFC. Each instance of NTT is associated with a language, as such the
textual information may be provided multi-lingually. The NTT may include a
Source Name Subtable (SNS).
A format for the transmission of data and events to the terminal.
These formats are defined in ISO/13818-6 standard. Their usage is defined in a
profile contained in DVB-MHP Specification Annex B. Essentially these
definitions provide a way of transmitting a Unix-like file system down a
broadcast channel. TSBroadcaster is capable of generating
OpenCable Application Platform, the US cable industry's middleware standard
specified by CableLabs. Also known as "tru2way". OCAP is Java
OCAP Automatic Test Environment. This is the OCAP version of the
ATE (see "ATE" above) which is used by CableLabs to
deliver the OCAP conformance tests to receivers under test.
OCAP ATE Host
Host server system for the OCAP Automatic Test Environment (ATE).
A project established by CableLabs, to standardize a cable network interface
and to build a retail market for digital cable terminals.
An out-of-band is a channel which is the combination of the forward and reverse
OOB channels. The OOB channel provides an IP-based
communication channel between a cable network and the set-top-box.
The portion of the cable RF range that is used to deliver system or service
information to a receiver. Its frequency range is generally 70-130 Mz.
The portion of the cable RF range that is used to deliver data from the home
receiver to the headend. Its frequency range is 5-40 Mz.
Profile, Demongraphics and Interest. An ATSC 2.0 term for data about
a specific TV viewer.
Packet Identifier. A unique integer value used to identify elementary streams
of a program in an MPEG-2 transport stream.
This standard describes a general syntax for data that may
have cryptography applied to it, such as digital signatures
and digital envelopes. The standard allows recursion, so that,
one envelope can be nested inside another, or
one party can sign some previously enveloped digital data.
A file format commonly used to directly store a private key along with its X.509 certificate.
A PKCS #12 file, and subparts thereof, may optionally be encrypted and signed.
These files can be created, parsed and read out with the OCAPSFG or OpenSSL pkcs12 commands.
Physical Layer Pipe – a portion of an ATSC 3.0 RF channel which has certain modulation and
coding parameters. One 6MHz channel may contain several different PLPs.
Program Map Table. An MPEG-2 table which provides data and location on
all TV services in the transport stream.
A type of MPEG Section. Specifically a private_section must be used when private data is
sent in Transport Stream packets with a PID value designated as
a Program Map Table PID referenced by the Program Association Table.
Quadrature Amplitude Modulation. A type of
typically used by US cable plants for in-band distribution.
Most common varieties of QAM used are 64-QAM and 256-QAM.
Quadature Phase-Shift Keying - A digital modulation technique which changes
the phase of the reference signal or carrier wave using four phases.
US cable headends often use QPSK modulation for the out-of-band
Root Certificate Authority.
A data path that goes from the subscriber to the cable headend. Also known
as Upstream, Reverse Path or Return Path.
RF - Radio Frequency
Analog electrical signals sent over the cable. Television signals are
modulated onto RF signals and are then demodulated by the
television's tuner or set-top-box.
Real-Time Object Delivery over Unidirectional Transport. A protocol used
by ATSC 3.0 to deliver service signaling and MPEG DASH segments. ROUTE is
a derivative of the FLUTE protocol mentioned above.
RSA - Rivest, Shamir and Adleman
Commonly used to describe a key which is asymmetric. Asymmetric keys have
separate private and public components based on prime numbers such that data
encrypted using one component can only be decrypted using the other
Receiver, or terminal, Under Test, a term used often with respect to the
MHP and/or OCAP ATE.
Service-based Transport Session Instance Description. An ATSC 3.0 SLS XML fragment
which provides the overall session description information for transport session(s) which carry
the content components of an ATSC 3.0 service.
Stewardship and Fulfillment Interfaces. A collection of interfaces defined
by CableLabs to support advanced services on multiple cable systems.
The Society of Cable Television Engineers, a non-profit professional
association responsible for development of standards,
their certification and provision of related information.
SCTE specification, set out in multipled parts, which describes a framework
for dynamically selecting and splicing advertisements. Such ads, may vary in length,
and subject matter. The splice may be into linear, stored, or switched video content.
Essentially SCTE-130 enables personalized and targeted advertising.
SCTE standard which defines an Emergency Alert signaling method for use by cable TV
systems. SCTE-18 defines a cable_emergency_alert() message in the form of an
MPEG-2 private_section(). MPEG-2 table_ID for this message is 0xD8.
SCTE standard which supports the splicing of MPEG-2 streams for the purpose
of Digital Program Insertion. This includes insertion of advertisements
and other content types. SCTE-35 defines how ad insertion control messages
(cue messages) may be inserted and used in TV broadcast systems.
Standard for Service Information delivered Out-of-Band for digital
cable television. OCAP set-top-boxes may receive channel maps
delivered in SCTE-65 format if delivered via DSG broadcast tunnels type 1.
A section is a syntactic structure that is be used for mapping all MPEG-2 (ISO/IEC 13818-1) defined
PSI tables into Transport Stream packets.
Service Information. Information that describes the TV services available on
the network. OCAP service information is defined by the SCTE 65 standard.
A file containing a unique code generated by applying a private key against
a known, reproducible, set of data. The converse operation of applying the
corresponding public key against the unique code will reconstruct the original
ATSC 3.0 Service Layer Signaling. Signaling information which provides
sufficient details for the discover and acquistion of ATSC 3.0 services.
Often SLS data is multicast to the address 239.255.M.N
where M is the major channel number and N is the minor channel number.
ATSC 3.0 Service List Table, provides the information for an ATSC 3.0 receiver
to build a basic service list. The SLT is carried in the LLS.
Service Measurement Summary Interface, a component of
which specifies a data model and transmission protocol for delivery of service
measurement summary information from an MSO system to an external entity.
The Service Map Table. An MPEG-2 table which contains service-level attributes for ATSC NRT
Services carried in the fixed-broadcast Transport Stream.
DSM-CC object carousel generator and transport stream encoder used by the MHP
and OCAP ATEs.
A type of Trigger that conveys application defined messages to an
application (typically an EBIF or OCAP application).
Short-form Virtual Channel Table. The S-VCT is a Service Information table defined in SCTE-65
with a table_ID of 0xC4.
There are three map types currently defined for S-VCT: the Virtual Channel Map (VCM),
the Defined Channels Map (DCM), and the Inverse Channel Map (ICM).
Broadcast service which uses several otherwise unused scanning lines
(vertical blanking intervals) between frames of TV pictures to transmit
information to receiving TVs. This service has been very popular in the
United Kingdom for many years.
A test harness provides a framework for building, execution and reporting
of tests results.
Specifically an MPEG transport stream, is a standard format for transmission and storage of
digital audio, video and associated data. The detailed structure of a Transport Stream is
specified in MPEG-2 Part 1. The transport stream structure specifies a container format encapsulating
packetized elementary streams, with error correction and stream synchronization features
for maintaining transmission integrity when the signal is degraded.
Transport streams differ from Program Streams in several
important ways: program streams are designed for reasonably reliable media, such as DVDs,
while transport streams are designed for less reliable transmission,
namely terrestrial, satellite or cable broadcast. In addition, a transport stream may
carry multiple programs.
A broadcast message that provides a synchronization mechanism to an
interactive TV application (such as an EBIF application). Triggers may be
embedded in the associated video program, or delivered via another means
such as the out-of-band. Triggers may also be used for the delivery of
unsolicited data to an application. Triggers may include application signals
and stream events.
is the interactive TV standard for use cable systems. It replaces the term
"OpenCable Platform" and is CableLabs' brand for the OCAP middleware standard.
An encoding solution and DSM-CC carousel generator which handles automatic
and scheduled playout of OCAP, ETV and MHP applications.
A legacy version of TSBroadcaster with QAM output, suitable for lab testing.
Multiplexor and play-out software used by the OCAP ATE to broadcast OCAP test
cases through ASI output.
An MPEG-2 transport stream player used by TSBroadcaster for output via
ASI or Gigabit Ethernet.
An OCAP application which is not bound to a particular service. It is present
across all of the TV channels. OCAP EPGs and the Monitor Applications are
Unbound Declarative Object
An ATSC 2.0 Declarative Object that is not bound to a particular terrestrial TV service.
User Service Bundle Description. Another component of ATSC 3.0 signaling, essentially a XML-based SLS
fragment which provides entry point information for the description and discovery of
an ATSC 3.0 service.
Usually used in the context of ETV, a User Agent is native application which
interprets EBIF binary code and renders images on the TV screen appropriately.
Video on Demand. A feature which allows TV viewers select (usually from the
program guide) a movie or program to be played almost immediately. Usually
VOD services are provided by VOD servers located in the cable company's
W3C Consortium - An organization formed to develop common protocols to ensure
interoperability and promote the World Wide Web.
eXtended Applicaton Information Table. An enhanced version of the
AIT used to signal unbound OCAP applications.
X.509 is an ITU-T standard for a public key infrastructure (PKI).
An application validator for OCAP, ETV-EBIF, MHP, ACAP and JSR-242 application
YouTube is a video-sharing website on which users can upload, share, and
Slang expression for very simple and cheap set-top-boxes that contain minimum
A Zone is a local area or subset of a