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ACKprior ON|OFF Default: OFF
Mode: Packet Host: AN
_________________________________ Parameters: _________________________________
ON - Priority Acknowledgment is enabled.
OFF - This feature is disabled.
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This command implements the Priority Acknowledge scheme described by Eric
Gustafson (N7CL), which proposes to improve multiple access packet performance
on HF and VHF simplex channels with hidden terminals. When a busy channel
clears, the acknowledgments are sent immediately, while data and poll bits are
held off long enough to prevent collisions with the ACKs. By giving priority to
data ACKs, fewer ACKs will collide with other station's data, reducing retries.
Digipeated frames are sent immediately. RAWHDLC and KISS force ACKPRIOR off.
These are the defaults for a P-persistence system with NO Priority
Acknowledgment:
ACKPRIOR OFF, PPERSIST ON, PERSIST 63, SLOTTIME 30,
RESPTIME 0, MAXFRAME 4, FRACK 5
The following are the recommended command settings for Priority Acknowledge:
1200 baud VHF packet 300 baud HF packet
ACKPRIOR ON ACKPRIOR ON
PPERSIST ON PPERSIST ON
PERSIST 84 PERSIST 84
SLOTTIME 30 SLOTTIME 8
RESPTIME 0 RESPTIME 0
MAXFRAME 1 - 7 MAXFRAME 1
FRACK 8 FRACK 15
HBAUD 1200 HBAUD 300
VHF ON (or TONE 3) VHF OFF (or TONE 0)
DWAIT doesn't matter DWAIT doesn't matter
Stations using neither the Priority Acknowledge nor the P-persistence schemes
should set DWAIT 73 for 1200 baud and DWAIT 76 for 300 baud work. Stations
using P-persistence but not Priority Acknowledge should set PERSIST and SLOTTIME
to the same values that ACKPRIOR stations are using.
Timewave and TAPR use some different command names to handle P-persistence.
The following table should help with the AEA/TAPR command differences:
TAPR_SLOTS MFJ SLOTMASK AEA_PERSIST Remarks
1 $00 255 Disables slotting
2 $01 127
3 84
4 $03 63 Default setting
6 42
8 $07 31 Very busy channel
12 20
16 $0F 15 Extremely busy channel
64 $3F 3
Timewave products calculate the TAPR ACKTIME value based on the setting of HBAUD.
The TAPR DEADTIME command is analogous to the Timewave SLOTTIME command.
4/91 A-10
