RadioBanter - View Single Post - Soundmodem-Userspace converse mode

Rob[_8_] · December 22nd 08, 10:29 AM posted to rec.radio.amateur.digital.misc

wrote:
I have read that with a regular external tnc you can go into converse
mode in which you can type a message and the tnc converts it to a
packet/packets. The packets can then be sent to another tnc
essentially setting up a simplex packet network. I have been playing
with APRS and have gotten the user-space soundmodem driver to work
with xastir perfectly.

I was wondering if there is anyway to use soundmodem in a type of
"converse mode" by just typing a message that is converted by
soundmodem? I have tried echoing from the command-line to /dev/
soundmodem0 but haven't been able to get it to work. I also tried
writing a small python script that would write a string to /dev/
soundmodem0, but that also did not work.

There is a difference between a modem and a TNC. A modem just converts
bits to tones and vice-versa. A TNC has a processor and can do
intelligent things like converting typed text into packets. A modem
cannot do that.
When using a modem, there has to be some application that performs the
packet layer functions. In Linux, this function can also partly be
performed by the kernel AX.25 functionality, but you still need the
application to setup the connections and provide the data.