Depending on the DSP mode, the I/O buffers vary between 6 and 16 bytes,
and the number of buffers transferred at a time also depends on the mode.
The interrupt routine transmits only 6 bytes (this is used for V21
modulation at least), however larger amounts are sent by polling the
device and sending at regular intervals. I don't know how long the
device buffer is in TAD mode but an experiment shouldn't be hard.
> How much time can I miss? I don't know. That depends on what v34 can
> handle.
In general The time we can miss depends on the other end.
It's configurable in USR Sportsters: Some S register says how long to
wait when a line goes dead before dropping it.
Around here there's a recommendation to increase the value..
For V34 there's the echo cancellor. If we miss, we have to make sure
the Tx and Rx sample times are still synchronised, by knowing how many
samples didn't go out, so that cancellation keeps working.
To know how many samples didn't go out, I think we have to keep the Tx
FIFO full in the interrupt routine. I don't know how to get the count
any other way.
-- Jamie
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