NAME

du − DU-11 synchronous line interface

DESCRIPTION

The files du0, du1, etc., represent interfaces to synchronous modems such as the Bell System 200-series synchronous DATA-PHONE® sets.  Read and write calls to du?  are unlimited, but work best when restricted to less than 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” characters must be supplied by the user.  Each read call returns the characters read from a single record.  Seven bits are returned unaltered; the eighth bit is set if the byte was not received in odd parity.  An error is returned if data-set ready is not present. 

FILES

/dev/du? 

SEE ALSO

dn(4). 

May 16, 1980  —  PDP-11 obsolete