What number would one "dial" to make a collect call back to Canada - - from Spain?

Could be either a Spanish or English speaking operator at the other end (or, for some, but not me, French).

A Spanish toll free number would be preferred of course, not one of those € 2 (Euro) calls .

I was thinking of "Canada Direct" - - and would love to know what the number would be to call via Telefonica (can't find info on how to dial in the local Paginas Blancas.