TTY_SILOTIME

   TTY_SILOTIME defines the interval at which the DMF32 hardware
   polls the input silo for received characters. The DMF32
   asynchronous terminal controller can delay the generation
   of a single input interrupt until multiple characters have
   accumulated in the input silo. TTY_SILOTIME specifies the number
   of milliseconds that the characters are allowed to accumulate
   prior to the generation of an input interrupt by the hardware.

                                  NOTE

      The remainder of this discussion is of interest to customers
      who use Digi Edgeport hardware.

   TTY_SILOTIME controls latency, trading throughput and system
   overhead for latency. The default value for TTY_SILOTIME is 8.
   This value is multiplied by 100 and is used as a count of the
   number of times to send a query to the device for more data after
   a character transmit or receive is performed.

   If no input (or no subsequent output) is seen after 800 responses
   to the query, the driver stops sending queries to the device and
   waits for an input interrupt. Reducing the TTY_SILOTIME value
   allows the device to buffer more data, with slightly higher
   latency.

   Increasing the value of TTY_SILOTIME makes the device more
   sensitive to latency but decreases buffering and overall
   throughput; it also adds more system and USB overhead. Setting
   TTY_SILOTIME to zero causes the driver to send input queries to
   the device continually. This setting causes the lowest latency,
   the highest system overhead, and the lowest throughput possible.