can I hook up a ethernet module and a sd card module together?

Hi, I have a ethernet module (not shield) and a SD card module, both work fine separately. But the problem is that both module use pin 11-13, so is it possible to make them both working together by making some adjustments? One more thing, if i use the ethernet shield, are those pins (11-13) on the shield free to use?

Thank you!

The Ethernet shield is basically an Ethernet module and SD-card module on the same board. They share the SPI bus (11-13 on the UNO) by having separate SlaveSelect pins: 10 for Ethernet and 4 for SD. Only one SlaveSelect pin should be LOW at any one time and only that module with the SlaveSelect low should be using the SPI bus. That's how the SPI bus is shared across multiple devices.

so is there a way to manually switch between them and hook them up together?

ttttkk: so is there a way to manually switch between them and hook them up together?

Manually switch between them like with a physical switch? The only reason to do that would be to have them share a SlaveSelect signal and that would prevent a sketch from using both. It could only use the device the physical switch was set for. If you do that be sure to have a pull-up resistor on the unused device SS line to keep it disabled.