I know of a timing problem in paclink-unix but the file sizes are in the
10k to 20k byte range. Could you please send the file you are trying to
send as an attachment to my personal email address, not the udrc
group. Also copy/paste the entire console session output so that I can
replicate your problem.

The AX.25 frame size is set in /etc/ax25/axports configuration file and
should be 255 bytes.

I only use direwolf as a sound modem. You should NOT be setting any
AX.25 parameters there.

Regarding Winlink message file sizes:

From a google groups thread (Adam KF7LJH)

ARES typically recommends no more than 5KB winlink messages. More than
than can risk your radio (and the gateway's radio) since the output
finals can get so hot because of the long transmission time.

Attachments are generally a bad idea with winlink. Keep it plain text
only.

From the Winlink site:
Message size maximum, including Attachments: 120000 bytes (compressed)

/Basil

jgindc1@... writes:

> I am sending/receiving Winlink messages using a Raspberry pi with the
> DRAWS hat. All is well as long as the messages/attachments are short,
> less than a couple of kBytes.
>
> When attempting to send longer messages/attachments, each transmission
> increases in time starting at about 4 seconds then climbing up to
> about 14-15 seconds at which time I get a fail message - "Exchanged
> failed: read udr0: connection timed out". I would like to set a limit
> to the maximum transmission period.
>
> I am unsure at which software level the maximum packet/frame length is
> determined. I have looked at direwolf.conf but did not see any
> reference to frame or packet length.
>
> Any suggestions would be gratefully received.
>
> John KM7LJ