Modes 1-6 & 8.
PSI BOX Reference
S.A. Talk Function. PSI Commanded To Talk By Controller.
____ _____________________________________________
0-12 No special function. PSI BOX sends its buffered data.
13
PSI BOX sends one byte indicating buffer contents status.
00 means no data in PSI BOX buffer.
01 means some data in PSI BOX buffer.
14
PSI Box sends the state of the RS232 port pins.
The PSI Box returns one byte which holds the state of the
handshake pins of the RS232 port.
A 0, zero bit means that the line is held true, +12 Volts.
A 1, one bit means that the line is held false, -12 Volts.
DTR is bit 0 decimal value 1 an output from PSI Box.
RTS is bit 1 decimal value 2 an output from PSI Box.
DSR is bit 2 decimal value 4 an input to PSI Box.
CTS is bit 3 decimal value 8 an input to PSI Box.
DCD is bit 4 decimal value 16 an input to PSI Box.
15
PSI Box sends an identification message, memory size and
software revision date eg P.S.I. BOX V4.3 02/05/90 32K.
S.A. Listen Function. PSI Commanded To Listen By Controller.
____ ________________________________________________
0-12 No special function. Data is buffered for output to port.
+15
13
PSI BOX flushes the RS232 or Centronics buffer.
PSI BOX accepts one byte of data from the controller.
Bit 0 decimal value 1 set means flush output buffer.
Bit 1 decimal value 2 set means flush input buffer.
14
RS232 only. The PSI BOX accepts one byte which speci-
fies the level of the RS232 port output pins RTS and DTR.
A 0, zero bit causes the line to be held true, +12 Volts.
A 1, one bit causes the line to be held false, -12 Volts.
DTR is bit 0, decimal value 1, an output from PSI BOX.
RTS is bit 1, decimal value 2, an output from PSI BOX.
The state of the Input cannot be set but only read.
Chapter 6
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