Hi Dean

I assume you mean "sounds like 1200bps packet" rather than 2400?

I doubt this is relevant but I had some issues with using the serial
port for PTT under soundmodem. Ended up running setserial and turning
the serial port "off" before use. (ie "uart none") I'd think though that
baycom mode would be simply a "synchronous" form of transmitting to/from
a standard serial port and wouldnt need to be turned off this way..

Since the whole thing should be synchronous at 1200bps I'd start looking
for any inter bit delays that may be being introduced. This I think
would be more commonly a RX rather than TX problem. I remember having an
older kernel that didnt recognise the 16650 UART properly and defaulted
to something without either a RX or TX buffer. Perhaps some playing with
setserial will help (defining the UART type also defines whether it uses
buffering. I think the kernel module allows you to change the buffer
size but I havent checked this)

You may also be able to capture the audio with your soundcard and make
some hard comparisons with a spec-an etc to determine where it falls down.

If you think it may be linux version/kernel dependent try the Knoppix
boot CD. I think there is also a ham radio version if AX25 support isnt
in the original

Apologies for not being more helpful

Cheers Bob W5/VK2YQA

data ham wrote:

After much searching and gleaning of details from various on-line docs,
including the AX.25 Howto, I have reached a dead end with an attempt to
find a new use for an old Baycom serial modem. The flavor of Linux is
Gentoo 2.6.11 r3