CARDS as I understand it:
Each team gets 50 cards to start the season but only 30 of them are designated for their playing roster. So, up to 20 additional players can be signed to “B” cards.
An example of a “B” Card player would be Belanger or Crete. I am not sure what they are signed to but for arguements sake let’s just say they are “B” Card players.
A “B” card player can play up to 10 games in the regular season and remain on their “B” Card; however, they can play additional games during the Christmas break that do not count towards their 10 game maximum. I am not sure what the dates are for that window.
Once the “B” card player’s affiliate team has been eliminated from playoff competition, they can be called up to the Major Junior club for the remainder of the season.
So, Belanger is a good example of a player likely to be a “B” card player. This may be a reason why we only dressed 5 D-Men at times, so they can protect his “B” Card status. Same with guys like the two Tourigny’s and Dick.
You only get 30 cards for your active roster. You don’t want to needlessly burn those spots. This is why a guy like Sirman played two games and was released. He was released prior to the NHL season starting and that is the time when players are officially assigned to cards. They don’t penalize teams by making them use cards on temporary players while guys are at NHL camps.
So, to recap:
50 total cards
30 active roster cards
“B” players can play 10 games plus addition games under certain circumstances
Cards are not transferred or renewed during the season and you cannot purchase or trade for more.
EDIT:
I forgot about one other scenario. If a team has a player skating in the NHL but has exhausted all of their cards, the player being sent down can still be added to their roster. For example, the Los Angeles Kings have Gabe Vilardi. The Kingston Frontenacs have used all 30 of their cards. LA can send Vilardi back and it would not affect their situation.