To consolidate what mhku has said, both Irish and UK
Sky cards work exactly the same. They have what I call a "sleep date". If they don't receive a "stay awake"message before the sleep date they temporarily stop working. Every time they receive a stay awake message, roughly every day, the sleep date is advanced and is about 5 to 6 weeks from the last stay awake message received.
Luckily (and unlike the similar facility of a Dragon Cam), CCcam can send the keep awake message to a card, provided that the Dreambox is turned on and that the tuner is receiving a channel (ANY channel) on the
Sky EPG; in practical terms virtually anything at 28,2º/28,5º.
Under these circumstances a sleeping card should wake up within 24 hours (48 hours at most). CCcam WILL wake up a sleeping card - for reasons I won't go into, I have a stock of (expired)
Sky cards, and I tried with one that had been asleep for a year or so. Within a few hours, Channel 4 and Channel 5 (which need an active but not necessarily subscription) card started to work again.