First filed in February 2008, the patent called "Auto Messaging to Currently Connected Caller" details a way for a user to send texts, emails and documents to a person while on the phone to them.
Apple described a scenario such as a conference call, and having the ability to send a document to all the people currently on the call without having the hang up first.
There is also the possibility of sending over a contact to someone, or forwarding them a picture without needing to cut your call short.
The patent suggests that data could be sent over a number of network options, such as GSM, GPRS, Edge, Wi-fi, WiMax and Bluetooth.
As with all patents, its definitely worth taking with a pinch of salt, and although this one seems both useful and doable, it hasn't cropped up in any phones since it was filed 2.5 years ago.
We'll be keeping our ears and eyes open for any news on Apple's next iPhone, so keep it locked to Stuff. tv and let us know below what you want to see in the 4th Gen iPhone.