As Huwyt_Nashi052 said, IR controllers are generally very flexible and allow for receiving/sending arbitrary low-to-medium frequency signals.
BL602 is no exception with the software mode the controller provides, giving you access to raw pulse lengths; for example I use it as a pulse frequency counter to interpret a BLDC driver's "speedometer" line, and there are countless other applications like controlling an eInk display's common anode/cathode line.