How to send data via Bluetooth in an iPhone application (a la putty)?

Question

iOS

Fellow developers! Prompt in what direction to look, where to esteem on such question.
It is necessary to send text commands to another Bluetooth device from a self-written software for iOs using iPhone4. Like a putty terminal. Simple, symbol-by-character, without any troubles.
Tell me, who knows, the easiest option.
Thanks in advance.