Throughput of Serout

Dear All,

I would like to know how many bytes I can send using Serout and the same is with Serin(who many bytes can I receive). Currently I am using N300 baud rate.

Is there any limitation from architecture point of view.

Currently in my implementation, I check for a "sync byte", once I receive that byte I would like to receive rest of the bytes, but can those "rest of bytes" be of any length?

Thanks in advance,
Mankan