Linux How does communication with kernel module from user space happen

Question

I am reading Embedded Linux Primer book and The Linux Kernel Module Programming Guide and I am confused about user space application communication with kernel module

User space App --> Device node/proc file --> kernel module ( which resides in /lib/modules/)

1) What is exact difference when we communicate with device node method ( /dev/ - with open,read,write,close calls) and /proc/file method ?