# Programme Delivery Control

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This article is about PDC/StarText teletext programme listings. For other uses, see [Startext (disambiguation)](/source/Startext_(disambiguation)).

**Programme delivery control** (**PDC**) is specified by the [standard](/source/Standardization) ETS 300 231 (ETSI EN 300 231), published by the [European Telecommunications Standards Institute](/source/European_Telecommunications_Standards_Institute) (ETSI). This specifies the signals sent as hidden codes in the [teletext](/source/Teletext) 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 called **PDC/StarText**.

In Germany and some other European countries, the older standard **video programming system** (**VPS**) is in use also known as format 2. Effectively, the two systems do the same thing and most modern [VCRs](/source/Videocassette_recorder) and stand-alone [DVD recorders](/source/DVD_recorder) work with both signals.

In digital TV (see [Freeview+](/source/Freeview%2B)), the feature [Accurate Recording](/source/Accurate_Recording) (AR) that was based on the PDC specification for analogue recording devices is now used for a [DVB](/source/Digital_Video_Broadcasting)-SI event based scheduling system. This was due to the BBC discontinuing the [Ceefax](/source/Ceefax) service.

## PDC Packets

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.

- PRF Set – Prepare for Record. This will tell a VCR to wake up and get ready. This happens about 40 seconds before the programme is active.
- PRF Clear – The VCR should be recording.
- RTI – Record Terminate/Interrupt – Tells the VCR to stop recording. This label is held for 30 seconds after the programme ends.

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.

## External links

Technical specifications and FAQ

- [ETSI standards](http://www.etsi.org)
- [ETSI EN 300 231 V1.3.1 (2003–04)](http://www.etsi.org/deliver/etsi_en/300200_300299/300231/01.03.01_60/en_300231v010301p.pdf), Specification of the domestic video Programme Delivery Control system (PDC)
- [ETSI EN 301 775 V1.2.1 (2003–05)](http://www.etsi.org/deliver/etsi_en/301700_301799/301775/01.02.01_60/en_301775v010201p.pdf), Specification for the carriage of Vertical Blanking Information (VBI) data in DVB bitstreams
- [ETSI TS 102 323 V1.5.1 (2012-01)](http://www.etsi.org/deliver/etsi_ts/102300_102399/102323/01.05.01_60/ts_102323v010501p.pdf), Chapter 11: "Accurate recording" and Annex A: "Example recorder behaviour"
- [CHARACTERISTICS OF A PROGRAMME DELIVERY CONTROL (PDC) SYSTEM FOR VIDEO RECORDING (1990)](http://www.itu.int/dms_pub/itu-r/opb/rep/R-REP-BT.1226-1990-PDF-E.pdf)
- ["Everything you ever wanted to know about PDC"](https://625.uk.com/pdc/)
- ["Padding versus Accurate Recording"](http://wiki.hummy.tv/wiki/Padding_versus_Accurate_Recording)
- [Original VPS invention (European Patent Office)](https://worldwide.espacenet.com/publicationDetails/biblio?locale=en_EP&CC=DE&NR=3313799) German and English

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Adapted from the Wikipedia article [Programme Delivery Control](https://en.wikipedia.org/wiki/Programme_Delivery_Control) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Programme_Delivery_Control?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.