trouble with 12C between iduino yun and uno

[joe123]

I am having problems with 12C communications between my Iduino Yun and a Arduino uno r3. I can have the Iduino request data (using Wire.onRequest on Uno) from the Uno and it works great, however when I have the Uno sending and the Iduino using Wire.onReceive its not picking up any data!? What are the SDA and SCL pins on the Iduino? Are they the same as the Uno? Are there any specific difficulties involved for this setup?