Digital Headend industry is very vast industry.So there are lot of technical terms which we use in this Digital Headend Industry.
We will discuss here most commonly used terms.
AC stands for Access Criteria. Access criteria is a 8 Digital Value and it used to scramble the services.Access Criteria is different for each service.
example for Access Criteria are ,
ACG stands for Access Crieteria Generator. As its indicates that ACG is used to generate the Access Criteria.
ASI stands for Asynchronous Serial Interface. ASI is a type of digital signal which we are using in old ASI digital headend.But now a days we are mostly using IP Headend. A ASI digital can also be conterted into IP headned using ASI to IP converter.
CAS stands for Conditional Access System. CAS is the most important part of the digital headend.CAS is used to Encrypt the servies so that it protects our data from other users.
ECM stands for Entitlement Control Message. ECM is encrypted. ECM contains the CW (Control Word) to give access to the subscriber for a particular program.
EMM stands for Entitlement Management Message.EMM contains the information of subscriber pacakage which need to activate.
ECMG stands for ECM Generator. ECMG did not support ECM repetition.
EMMG stands for EMM Generator.EMMG initiate the connection to MUX.
SCR stands for Scrambler. SCR is responsible for scrambling of data for MPEG 2 Transport Stream.
MUX stands for Multiplexer.Multiplexer is used to multiplex different SPTS (Single Program Transport Stream) into single MPTS (Multi Program Transport Stream).
(11) PSI SI Tables
PSI stands for Program Specific Information while SI stands for Service Information.These tables are included with services into the MUX.Get more information on PSI SI Tables
SPTS is known as Single Program Transport Stream.As its name indicates that SPTS contain only single program or service in it.If there is a 8 Channel Encorder then this encorder will generate 8 SPTS and UPD port can be same for all SPTS.
So there will be separate Transport Stream for single channel like
where 5024 is the udp port.
MPTS stands for Multi Program Transport Stream. All of SPTS are send into the MUX. MUX multiplex these SPTS and provides MPTS as output.For example a MPTS can be,
where 60001 is the UDP port which will be same for all Transport Stream.
CW is known Control World.Data stream is scrambled with the 48 bit key.This is called the Control Word where this 48 Bit key is the secret key.
CP is known as Crypto Period.Many service providers changes the control word in every 2 seconds or 10 seconds.This period is know as Crypto Period.
OTA stands for Over The Air.Basically this is the software which commands threw service providers to their STBs to upgrade the Release of STBs.
SMS stands for Subscriber Management System. SMS is a server which we use at headend and SMS is connected to CAS via Management cable.The SMS server sends the commands to the CAS server to Activate ,Deactivate and Blacklist STBs.SMS server also sends the command to CAS server like
Bootup Channel Command
On Screen Display
OSD is called the On Screen Display.As discussed above OSD command can be send threw SMS server as well as CAS server to one or all the STBs available in the Field.For Example
EPG stands for Electronic Program Guide.EPG contains all the information about the programs which are currently broadcasting and to be broadcasted.
Get More Info Electronic Program Guide
(20) EPG Number Or LCN
LCN stands for Local Channel Number of service it is also known as EPG Number.
Know More About What IS ECM And EMM In Digital Headend