what id different between ethercard and ether sheild

i have ehtercard and many project in internet using ether shield
is their any main different in programming code
or need to modified except the libraries


Can you please provide a link to the ethercard that you have ?

The ENC28J60 chip used on the EtherCard only gives Ethernet access. The TCP/IP network stack is implemented in the library leaving the Arduino with very limited SRAM to work with. The official Ethernet Shield (and clones) use a chip that includes the TCP/IP stack.