Each radio receiver has a unique ID that once paired will only talk to one transmitter. Some Transmitters have the ability to store many UIDs so you can operate them from one remote.
Awesome. So I'm betting a low-end unit like a Heng Long does not come with provisions to store multiple UIDs. Not that I care - as long as each Heng Long I buy will play nice with other tanks, that's fine with me.
Steve