Currently, I'm developing Bluetooth applications using AT89C51.

To communicate with the bluetooth device, I need to send a string of commands through the serial port. The bluetooth device will then return a string of bytes to indicate the status/result of the command.

The problem is, this device will not always return the same amount of bytes. Sometimes, it'll return 5 bytes. OTher times, it will return 7 bytes. Another problem is, the string of bytes received from the bluetooth device is not NULL terminated. That means there is no unique final byte to determine the END OF STRING.

Is there a way to detect the end of string?