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PK-88 OPERATING MANUAL
PACLEN 'n'
Parameters:
'n' -
0 to 255 specifies the maximum length of the data portion of a packet.
0
-
Zero is equivalent to 256.
PACLEN sets the maximum number of user data bytes to be carried in each packet's
'information field.' 'User data' means the characters you actually type at your
keyboard (or send from a stored file).
The PK-88 automatically transmits a packet when the number of characters you type (or
send from disk) for a packet equals 'n.' This value is used in both Converse and
Transparent Modes.
Most keyboard-to-keyboard operators use the default value of 128 bytes for routine
VHF/UHF packet services.
Experiment with different values for MAXFRAME and PACLEN to find the combination best
suited to your operating conditions - especially if you are transferring files.
•
The lower the value of PACLEN, the greater the probability of getting packets
though the link without 'hits' or retries.
•
Increase PACLEN to 256 byes (set 0) if transferring files to a nearby station
over a high quality path.
•
Reduce PACLEN to 64, or even 32 when working 'difficult' HF radio paths.
•
If the radio link is good, an optimal relationship will exist between the
parameters set by these commands. Set PACLEN so that the maximum number of
characters outstanding doesn't exceed the receive buffer space of the TNC
receiving the data.
It is not necessary that two TNCs be set to the same PACLEN value to exchange data;
however, some TNCs may not be compatible when frames contain more than 128 data
characters.
NOTE:
The FRACK counter begins counting from the first flag of
each frame. If MAXFRAME is set to 7 and PACLEN is set to
maximum (0), FRACK should be lengthened to prevent the
distant station's ACK from colliding with your possibly-
premature retry.
Mnemonic: PACL
5-73
Default: 128
COMMAND SUMMARY
PK88-155
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