Cryptovision in Ireland

[BarryMDublin]

Following an attempt in the late 1980s to use Discret 12, Ireland's largest cable TV operator, Cablelink adopted the Cryptovision encryption system during the 1990s for use on its pay-TV channels and MMDS in Dublin, Waterford and Galway.
The system was developed by Tandberg in Norway and the first generation of decoders was built by Omnitron in Ireland.

The decoders had an RF loopthrough, which could tune any 8MHz wide TV channel from 48MHz to 860Mhz, with a UHF modulator to view a decoded channel with mono audio. Alternatively, the decoder could be left in baseband mode where a TV would be tuned into an encrypted channel on the cable network. The decoder connected via Scart would recognise the valid decoding authorisation and switch the TV to the decoded picture. In this way, the TV would retain the stereo sound on NICAM.

The audio was never encrypted. The system was cardless and all decoders were individually addressable by the cable company.

Here are some pictures of the Irish-made decoder.

 

[BarryMDublin]

Continuing the story:

In the mid 1990s a second generation of Cryptovision decoder was commissioned with established manufacturer Pace UK.
Many satellite users will be familiar with the styling of the unit, being obviously based on their widely popular satellite receivers.

The technical review within Cablelink was mixed. The new decoders did not have a baseband facility like the originals. However, they did have an innovation where the NICAM stetero was looped though on the UHF modulator output. This meant that a customer could switch on their TV and watch all channels, clear and encrypted, in stereo sound through the decoder modulator.

But there was a problem with the first few hundred decoders. Customers were complaining that some channels being viewed through the modulator output had horizontal lines of interference moving up and down the screen. When Cablelink technicians investigated, it was found that the interference in these decoders was due to a daughter-board mounted on top of the motherboard. The daughter-board was found to be emanating RF harmonics co-inciding with the vision frequencies of the 8MHz VHF channel spacing.

The affected decoders had all to be sent back to the UK for re-work. This took several months and involved replacing the daughter-board with a single chip.

There was another problem. When watching a clear channel through the decoder, spurious graphic symbols would pop up on screen. These could be cleared with a press of a button on the remote control, but they popped up again sooner or later! An annoying quirk.

Another notable effect was that if the decoder did not recognise a valid subscription to a pay-channel, the unencrypted sound would mute and a No Access graphic would appear on screen.

Here's an example on YouTube:

When NTL took over Cablelink in the early 2000s, they introduced their own digital pay-TV system and Cryptovision was phased out.

 

[Captain Jack]

Fascinating story - thank you! Are there many decoders available on the second hand market? I'd love to get my hands on one of those.

 

[BarryMDublin]

Fascinating story - thank you! Are there many decoders available on the second hand market? I'd love to get my hands on one of those.

Doubt it. I've never seen any redundant ones in the wild. When NTL took over, they just swapped out the analogue decoders for digital ones. I don't know what happened to the analogue decoders, but I would like to think the components within them were recycled in some way.

 

[dreambox1959]

i start to work on TUDI12 decoders loan to me by Barry.
the 2 decoders works again !
the D12 encoder is arrived today , inside there is 10 card full of components : 6 cards for stereo sound , 3 cards for video , one card for µP .
the logic board is made with a 8031 set (eprom ram latch ) and a RT86 + nmc9306 .

 

[steeviebops]

Lovely stuff! An old friend of mine in Dublin had Sky Sports via Cablelink with the gen 1 decoder.

 

[planeS]

My best friend had the gen 1 decoder back in 1992 Sky Movies Plus ,The Movie Channel later Sky Sports which was snowy reception...By the time Sky Sports hit big the Premiership, when I was working I got the gen 2 decoder in late 1995 was great on screen displays etc also the Movie Channels ,Sky Sports 1 and 2 later came 3 also CNN, and Disney Channel.Sadly NTL took over digital Decoders came in have to say the Pace NTL decoder was the best.