USER'S GUIDE
ADVANCED PACKET OPERATION
PK232UG Rev. B 9/86
5-11
102
5.5.4.5.
MAXFRAME
The AX.25 protocol permits the transmission of several packets without waiting for an
acknowledgment. The number of packets that can be sent before acknowledgment is
known as the "window". The window concept permits more efficient channel use if
large amounts of data are being transferred.
The
MAXFRAME
command sets the maximum number of packets which your PK-232 will
send before waiting for acknowledgment. (This doesn't mean that your PK-232 will wait
until several packets have been typed before transmitting.)
MAXFRAME
, in combination with the
PACLEN
command (which sets the maximum num-
ber of characters in a packet), determines how much information can be sent in a sin-
gle burst transmission. The best combination for efficient data transfer depends upon
channel quality and the rate at which the terminal can process data.
For a 1200-baud terminal rate, begin with a combination that produces about 300 char-
acters outstanding at one time.
5.5.4.6.
CHECK
The
CHECK
command sets a connection timeout specified in multiples of ten-second in-
tervals. This timeout function prevents your PK-232 from remaining connected to a dis-
tant station when the other station disappears for longer than the specified time. Your
PK-232 uses this time somewhat differently, depending on the setting of AX25L2V2.
If
AX25L2V2
is
OFF
(a pre-Version 2.0 connection), the link is preserved by initiating a
reconnect call; the PK-232 returns to the "connect-in-progress" state and sends connect
request (SABM) frames. In addition, the PK-232 adds a random time of up to 30 sec-
onds each time
CHECK
occurs in a given connection.
5.5.4.7.
RESPTIME
The
RESPTIME
command sets the delay between the receipt of a packet and the trans-
mission of the acknowledgment packet. This delay is used to prevent collision between
an acknowledgment and another packet from the sending station.
RESPTIME
is mainly
necessary in file transfers. For normal service,
RESPTIME
is best set to 0 (zero) by the
station sending the file.
The station receiving the file in a file transfer should set
RESPTIME
to 10 (default) or
12.
5.5.4.8.
PACTIME
The
PACTIME
command sets packets transmission timing in the Transparent Mode. You
can choose the way packet transmission is timed. It's best to send packets at regular
intervals if you're typing manually to a remote computer.
If your computer is operating a remote-host or bulletin board program, send packets
after an interval without further input from the host or computer.
Use the
CPACTIME
command to enable
PCTIME
in Converse Mode.
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