Im planing to purchase three NL-2511CD+EXT2 Senao pcmcia cards and use them on my mikrotik router . It is not a routerboard it is a pentium 4 that I have build up using mikrotik 2.8 os. Anyone can tell me if OS is going to recognize the Senao cards or not?

Yes, It does. I have 3 router boards with two of these cards in each one.