Thank Lily and Mrkirkland for answering my question.
But I do not understand what it exactly means that "if the travel cards end in CA", is it a special card with the letter "CA" at the code end? Do I have to specify when I purchase it?
Also, a related question: if two person travel together, do we need to buy two cards, one for each person, or we can just have one card and use it to but two tickets whenever we take the bus or train?
Thanks a lot.