> >> So .. ok .. txtail is important. Couldn't we use some fixed (or computed)
> >> value which couldn't be mis-configured ?
> >> (driver/baudrate/anything dependant)
> >
> >Yes and no. With current available modem designs sure. But not with a future
> >modem which does for example a convolutional FEC with long interleaver.
>
> If the modem needs a delay it should be responsible for creating the
> appropriate delay. The software should not be responsible for operation of
> the modem.
That�s true. It should also be responsible for generating the txdelay
via the CTS line. As another major influence of this parameter is the
RF design (PLL lock delay etc.) a modem should be locate inside the
transceiver. As a transceiver requires a little controller anyway
(PLL divider ratio programming) it could also do transmitter keying
sequencing and CTS line control.
But since we must also support old equipment we have to provide
software-txdelay and txtail which is - at least for SCC based devices -
a little bit problematic due to the fact that the resolution is given
by system timer intervals (one jiffy, 10ms).
-- Jens
