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<strong>PK</strong>-<strong>232</strong> OPERATING MANUAL<br />
PACKET RADIO<br />
Transmission of data:<br />
7C F0 B0 65 10 F0 Test <br />
3E38 shifted 5832 shifted [I, P; 0, 0]<br />
short dest. short source CTRL PID text<br />
WAIABC sends data to WB2XYZ in Packet Lite format. The address field<br />
consists of the short address from WB2XYZ's UA frame, reversed and<br />
left-shifted. The added bits come from AX.25 version 2.0's command and<br />
response bits, and the end-of-address bit.<br />
Acknowledgment of data:<br />
BO 64 7C Fl 31<br />
5832 shifted 3E38 shifted (RR,F;l)<br />
short dest. short source CTRL<br />
WB2XYZ acknowledges the data from WALABC. The address field is<br />
reversed. This is the shortest length frame possible in Packet Lite. 4<br />
address bytes + 1 CTRL byte + 2 flags + 2 CRC bytes = 9 bytes.<br />
Every 10 minutes the stations must identify using both long and short<br />
addresses:<br />
W B 2 X Y Z -0 W A 1 A B C -0 [RR,P;0] 0l 3E 38 58 32<br />
destination ⏐ source ⏐ CTRL PID ⏐ short address<br />
W A 1 A B C -0 W B 2 X Y Z –0 (RR,F;1) 01 58 32 3E 38<br />
destination ⏐ source ⏐ CTRL PID ⏐ short address<br />
Either station may initiate the ID exchange.<br />
Disconnect:<br />
W B 2 X Y Z -0 W A I A B C -0 DISC 01 3E 38 58 32<br />
destination ⏐ source ⏐ CTRL PID ⏐ short address<br />
Disconnect acknowledgment:<br />
W A 1 A B C -0 W B 2 X Y Z -0 UA 01 58 32 3E 38<br />
destination ⏐ source ⏐ CTRL PID ⏐ short address<br />
At the end of the connection, the two stations must once again identify<br />
using both long and short addresses.<br />
Timewave firmware supporting Packet Lite also contains code that<br />
permits monitoring of Packet Lite and extended AX.25 frames.<br />
Packet Lite Shortened Address Technical Details<br />
The Packet Lite address field consists of 26 bits distributed over 4<br />
bytes (or 'octets', as the AX.25 Spec calls them). These bits are<br />
considered to be two groups of 13 bits each, roughly equivalent to a<br />
destination and a source ID. If we label the bits A-Z and show their<br />
use in the address field of a Lite frame, the bits are distributed as<br />
follows:<br />
A B C D E F G 0 x H I J K L M 0 N 0 P Q R S T 0 y U V W X Y Z 1<br />
2 /93 4-30<br />
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