after enabling router ports and before any config why I get connectivity on link R---SW2960 and no connectivity on link R --- SW2950
and the port is enabled on SW 2950
but I get this line on show command
Switch#show int fa 0/1
FastEthernet0/1 is down, line protocol is down (disabled)
... or it could be that you are using crossed cables. Between a router and a switch, you should use a straight cable. The 2960 has auto-crossover detection, but the 2950 does not, so the 2960 can compensate for having the wrong type of cable.