"WHAT IS PROTOCOL -BOFV1.1 ?"
 Dr. Lichen Wang

IrDA standards are specified in layers. Some layers are 
mandatory while others are optional. The mandatory layers 
and the current version numbers are:

IrPHY, Version 1.3
IrLAP, Version 1.1
IrLMP, Version 1.1

Some of the optional layers are:

TinyTP, Version 1.0
IrCOMM, Version 1.0
OBEX, Version 1.0

Within each layer, some of the features are mandatory 
and some other features are optional. The mandatory data 
rate is 9.6 Kbps. Other data rates are optional. Data 
rates lower than 576 Kbps are asynchronous and share the 
same data format. Your specific question about BOF is 
about this asynchronous format used by IrDA standards.

Answer: The BOF for this data format is 0xC0. 

In the earlier version of IrLAP (i.e. Version 1.0), it is 
specified that the transmitter side may be required to send 
extra BOFs. Meaning that it may be required to send a series 
of more than one 0xC0 to start a frame. However, the receiver 
side is only required to detect the last one of this series 
of 0xC0.

In IrLAP Version 1.1, this is modified. The recommended "Extra 
BOF" is 0xFF instead of 0xC0. The BOF is still 0xCO. This means
the transmitter side may be required to send a series of 0xFF 
followed by one single 0xC0 to start a frame. The receiver side 
is still only required to detect the last 0xC0. 

Please note that the schemes used in Version 1.0 and 1.1 are 
completely compatible with each other. The scheme recommended 
in Version 1.1 works more reliably in most of the hardware 
systems.