dfa(4)dfa(4)Namedfa - DFA01 communications interface
device dz0 at uba0 csr 0160100 flags 0x0 vector dzrint dzxint
The DFA01 contains two DF224-compatible modems with a DZQ11-compatible
interface. Each line attached to the DFA01 behaves as described in See
for the encoding. Lines may operate at 300, 1200, or 2400 baud. The
DZQ11 interface is capable of baud rates up to 9600 baud, but, because
the modem is restricted to speeds of 300, 1200, and 2400 baud, all
other baud rates are considered illegal and pass meaningless data.
A flags field of 0x0 must be specified to indicate that the lines are
to be treated as modems.
An entry of dfa01 should be used to describe the 2400 baud autodial
attributes used by such programs as and For pulse tone dialing at 2400
baud, an entry of dfa01-p should be used. To dial at 1200 baud, the
dfa01-1200 or dfa01-1200p (pulse dial) should be used. To use the
DFA01 autodialer, the terminal line must be set to no parity.
Any entry in the file that specifies an ACU type of dfa01 must specify
no parity. The following example shows how a correct entry in the file
dial2400|2400 Baud attributes:\
The driver normally uses its input silos and polls for input at each
clock tick (10 milliseconds) rather than taking an interrupt on each
will produce four terminal lines for the DZQ11 interface. The second
and fourth lines are the actual modem lines. The first and third lines
pass status information when the modem is on line.
dz%d: receive fifo overflow.
The character input fifo overflowed before it could be serviced. This
can happen if other devices heavily utilize the bus and CPU, preventing
interrupts from the DFA01 from being serviced. This may cause a few
input characters to be lost to users. It is not serious.
See Alsotty(4), acucap(5), MAKEDEV(8)