combination of 26 bits, to avoid conflicting with another Lite QSO.
In either case, the sender of the original SABM must accept the 26
bits in the UA frame, reversing the address order for its own
transmissions.
Transmission of data:
7C F0 B0 65 10 F0 Test <CR>
3E38 shifted 5832 shifted [I,P;0,0]
short dest. short source CTRL PID text
WA1ABC sends data to WB2XYZ in Packet Lite format. The address field
consists of the short address from WB2XYZ's UA frame, reversed and
left-shifted. The added bits come from AX.25 version 2.0's command
and response bits, and the end-of-address bit.
Acknowledgment of data:
B0 64 7C F1 31
5832 shifted 3E38 shifted (RR,F;1)
short dest. short source CTRL
WB2XYZ acknowledges the data from WA1ABC. The address field is
reversed. This is the shortest length frame possible in Packet Lite.
4 address bytes + 1 CTRL byte + 2 flags + 2 CRC bytes = 9 bytes.
Every 10 minutes the stations must identify using both long and short
addresses:
W B 2 X Y Z -0 W A 1 A B C -0 [RR,P;0] 01 3E 38 58 32
destination | source | CTRL PID | short address
W A 1 A B C -0 W B 2 X Y Z -0 (RR,F;1) 01 58 32 3E 38
destination | source | CTRL PID | short address
Either station may initiate the ID exchange.
Disconnect:
W B 2 X Y Z -0 W A 1 A B C -0 DISC 01 3E 38 58 32
destination | source | CTRL PID | short address
Disconnect acknowledgment:
W A 1 A B C -0 W B 2 X Y Z -0 UA 01 58 32 3E 38
destination | source | CTRL PID | short address
At the end of the connection, the two stations must once again
identify using both long and short addresses.
AEA firmware supporting Packet Lite also contains code that permits
monitoring of Packet Lite and extended AX.25 frames.
Packet Lite Shortened Address Technical Details
The Packet Lite address field consists of 26 bits distributed over 4
bytes (or octets, as the AX.25 specification calls them). These bits
are considered to be two groups of 13 bits each, roughly equivalent to
a destination and a source ID. If we label the bits A-Z and show
their use in the address field of a Lite frame, the bits are
distributed as follows:
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Содержание PK-900
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