Programme delivery control (PDC) is specified by thestandard ETS 300 231 (ETSI EN 300 231), published by theEuropean Telecommunications Standards Institute (ETSI). This specifies the signals sent as hidden codes in theteletext service, indicating when transmission of a programme starts and finishes.
PDC (also known as Enhanced Teletext Packet 8/30 Format 2) is often used together with StarText, enabling the user to select a programme to record using specially coded teletext programme listings. The combination of features is often calledPDC/StarText.
In Germany and some other European countries, the older standardvideo programming system (VPS) is in use also known as format 2. Effectively, the two systems do the same thing and most modernVCRs and stand-aloneDVD recorders work with both signals.
In digital TV (seeFreeview+), the featureAccurate Recording (AR) that was based on the PDC specification for analogue recording devices is now used for aDVB-SI event based scheduling system. This was due to the BBC discontinuing theCeefax service.
PDC is transmitted once a second in special packets addressed as magazine 8 and text row 30. Since this row is not displayable it does not interfere with normal pages. Packet 8/30 has various formats specified by ETSI and PDC is format 2. Each packet 8/30 format 2 also has a label number and there can be up to four labels transmitted at a time. Each label contains the scheduled start time and date for a programme and flags to indicate the state. Each programme is assigned a label and in general a label will follow this sequence.
There are complicated rules for the case where a programme is interrupted by another one as in the case of a film with a break for news in the middle.
There is also a TIMER flag that indicates that there is no valid PDC and that the VCR should use its own timer.
Technical specifications and FAQ