The PR_BCAST packet format allows a station to broadcast its callsign and associated link layer addresses to satisfy the amateur regulations. It can also be used for other purposes, as described in the next section.
All broadcast packets include the callsign of the transmitting station
as the source address. This
is a fixed 10-octet field. The callsign is expressed in 7-bit ASCII, with the
most significant bit of each octet off (i.e 0). The callsign is `big-endian',
i.e the first characters of the source callsign come first in the field.
If the callsign is shorter than 10 characters, the unused octets have all
their bits off (i.e 0). The callsign should be represented by the following
characters only
:
`A' to `Z' inclusive, `0' to `9' inclusive, `-' and `/'.
Thus, for example, the callsign VK1XWT would be represented by the 10 octets 86, 75, 49, 88, 87, 84, 0, 0, 0, 0 (decimal).