Helllllooooo everyone! I haven't made a guide in a while, but since a few minecraft updates were sent out, there's been new things to discover! Enjoy!
You'll need four chests
An optional amount of hoppers
And two redstone comparators (optional)
Place a chest at one spot you'd like to send/receive from.
Place down hoppers (while crouching) connected to each other to the other sending/receiving point. Make sure the tails of the hoppers are connected to the ones before them. If you are confused, look.
You can't see it, but (while crouching) add a chest on top of the last hopper.
Add a redstone comparator (optional)
While crouching, add a block of your choice on top of the chest on the hopper. Then add a chest on top of that.
On the other end, crouch and add three blocks. Then add a chest on it.
Crouching again, connect the third block to the other chest with hoppers.
Delete the blocks and add another hopper under the chest. Make sure it looks like the picture
Again optional, add a redstone comparator next to the chest that's on top of the one that doesn't have one next to it.
How it works: put something in the chest on top of the hopper. If you did the steps right, it should go through the hopper to the other chest.
And if you added the comparators, it will light up when the message is received. The light will go out when you take the object out of the chest. Enjoy, and farewell!