Kantronics KPC-9612 Plus, Руководство пользователя

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Once the TNC detects a clear frequency it will wait SLOTTIME (times 10 milli-
seconds). Then, if the channel is still clear, it will generate a random number. If
this number is smaller than the setting of PERSIST the TNC will transmit. If it is
larger it will wait another SLOTTIME and then generate another random number
and again decide whether to transmit or not. When using PERSIST and
SLOTTIME you should set DWAIT to 0, since both will be used if specified.
As an example, let’s assume that PERSIST is set to 63, and SLOTTIME is set to
10. This value of SLOTTIME results in a random number being generated every
100 milliseconds. When the TNC sees that the channel is clear, it waits 100 ms,
then generates a random number between 0 and 255 (inclusive). If, in our exam-
ple, the number was 83, then the TNC would not start the key-up of the transmit-
ter since 83 is greater than the 63 PERSIST value. Instead, it would wait an
additional 100 ms, and if the channel is still clear, generate a new random num-
ber. This time, let’s say it comes up with the number 27. Since this is less than the
PERSIST value, we now start the key-up of the transmitter to send the packet.
Txdelay
TXDELAY should be adjusted to allow your radio sufficient time to switch from
receive mode to transmit mode and develop full power output. If the TNC sends
the packet before the radio is at full power, the beginning of the packet will be
lost and no one will be able to decode it. TXDELAY also allows the station you
are talking to sufficient time to switch from transmit mode back to receive mode.
The TNC sends flags during the TXDELAY period, so if someone has this set ex-
tra long you will hear a repetitive sound at the beginning of the packet.
Frack (Frame Acknowledgment Time)
If the TNC expects an acknowledgment of a packet it has sent, it will wait
FRACK seconds for the acknowledgment. If the acknowledgment is not received
it will either send a poll or retransmit the packet, depending on the setting of
AX25L2V2. When digis are used, extra time is allowed for each transmission us-
ing the following equation:
FRACK * ((2 * n) + 1) seconds
where n is the number of digipeaters. The lower the baud rate (HBAUD) the
higher this parameter should be set, because everything is slower. The length of
Packet Mode of Operation Modes of Operation
KPC-9612 Plus v 8.2 115 User’s Guide