glenda.party
term% ls -F
term% pwd
$home/manuals/unix_v7/4/du
term% cat index.txt
DU(4)                      Kernel Interfaces Manual                      DU(4)



NAME
       du, dp - DU-11 201 data-phone interface

DESCRIPTION
       The  dp0  file  is a 201 data-phone interface.  Read and write calls to
       dp0 are limited to a maximum of 512 bytes.  Each write call is sent  as
       a  single  record.  Seven bits from each byte are written along with an
       eighth odd parity bit.  The sync must be user supplied.  Each read call
       returns  characters  received from a single record.  Seven bits are re‐
       turned unaltered; the eighth bit is set if the byte was not received in
       odd  parity.  A 10 second time out is set and a zero-byte record is re‐
       turned if nothing is received in that time.

FILES
       /dev/dp0

SEE ALSO
       dn(4)

BUGS
       The name dp0 is a historical dreg.



                                                                         DU(4)