Xerox 4219/MRP User Manual
D.
Coax communications buffer
This appendix describes a memory area known as the
communications buffer that is used by all coax emulations.
communications buffer that is used by all coax emulations.
Communications buffer
The communications buffer (figure D-1) contains a character
buffer and an extended attribute buffer. Each of these buffers
contains 4KB of storage.
buffer and an extended attribute buffer. Each of these buffers
contains 4KB of storage.
The first 80 bytes of the character buffer contains the printer
control information area (PCIA). The first 80 bytes of the
attribute buffer contains the extended PCIA.
control information area (PCIA). The first 80 bytes of the
attribute buffer contains the extended PCIA.
The remainder of the character buffer is a message area which
contains data and commands necessary for printing. The
attribute buffer can contain additional information about how
each character prints.
contains data and commands necessary for printing. The
attribute buffer can contain additional information about how
each character prints.
Figure D-1.
Communications buffer
Ext. PCIA
Character Buffer
Extended Attribute Buffer
X‘0000‘—X‘004F‘
described on the
following pages
described on the
following pages
X‘1000 to 104F‘
not used
X‘1FFF‘
PCIA
X‘0FFF‘
XEROX MRP FAMILY COAX COMMAND REFERENCE
D-1