PDC Live

Recent Decoded Packets

Packets are recorded off air continuously by the teletext adaptor but batched for the web page every 20 minutes at most. Here is the most recent batch after being fed through my decoder:

Currently tuned to BBC1 (Wenvoe)

               interleave PRF analogue audio
times and number of     | MI| |          country   start start programme
copies of same packet   | | | |      ? ?  -network date  time  content  
---------------------  -- - - ------ --- --------- ----- ----- ---------

For comparison, here are the same packets before decoding:

                    number of copies of same packet
first and last      |  de-hammed bytes:
times received      |  |main index page|in|PCS|CNI|day|mon|hr|min|  CNI  |PTY|
----------------- ---  -------------------------------------------------------

Sometimes the two lists above don't quite seem to correspond. This is likely to be because of reception errors, which show up in the de-hammed bytes as 2-digit hex values. Most errors are recoverable, so the decoder doesn't see them. Unrecoverable errors show up in the byte log as FF.

The times on the left are copied directly from the Teletext clock, sent as ASCII in packet 0. This information is not protected by hamming, so is more vulnerable to reception errors than the bytes in the PDC packet.

To understand what's going on, it might be a good idea to look at the description of Teletext transmission and format of packet 30 type 2.

Please tell me if you know anything more about the format of this packet so I can further improve the information on these pages.

If you would like more data to play with, you can look at extracts from the log of all the PDC packets recorded since 22 July 1996.

This page was generated by decode.cgi on Tue Apr 16 08:22:36 BST 2024. It has been read since it was created on 22 July 1996. decode.cgi was last updated 05 December 1996.

Please send comments to Robin O'Leary pdc at ro dot nu