16 bits at 1200bps is ~13ms, an arduino should have no problem doing 1200bps
Unfortunately it's not the "bits" that are the problem with AX.25.
Once the initial connection is established, data is transferred in frames - I (information) frames to be specific.
Fields in a frame:
Flag (8 bits), Address (112 to 560 bits), Control (8 bits), PID (8 bits), Information (our 16 bits), FCS (16 bits), Flag (8 bits) -
Therefore we have to transmit a WHOLE BUNCH more than our 16 bits of data to satisfy the AX.25 protocol requirements.
Oh - and the frame, once received, must be acknowledged back to the sender before the sender will send the next frame.
Sigh - AX.25 was not the best implementation. Why I'm asking the group mind for ideas.
Thanks,
Bill