in reply to: number of hart preamble posted by vaibhav on 19 January 2010 at 18:28:01.
Yes it may. Some probes may 'eat' one preamble octet. The preamble allows the electronic circuit to setup the receiver (e.g.) and it depends on the construction of the electronics how fast this works. Also the sender needs some time to establish the carrier. This may 'eat' a preamble too.
However this is the reason why it is not only one preamble octet (byte) to be sent out which is specified.
However from my experience the best practice is to send 5 preambles. The receiver software has to accept the start delemiter after 2 preambles. This allows 3 preamble octets to be 'eaten'.