Centronics Leds; Selecting The Direction Of The Centronics Port - Brainboxes PS-307 User Manual

PSI BOX Reference
Unlike the two other ports, the Centronics Parallel port is
NOT bidirectional. It can act EITHER as an input OR as an
output. It can not change over in mid stream from input to
output or vice versa.
______________ _

Centronics Leds.

There are two LEDs dedicated to the Centronics Parallel
port. LED 5 and 6 are used to indicate the flow of data to the
Centronics Parallel port.
LED 5, CENTR O/P, flashes whenever the Centronics
Parallel port of the PSI BOX sends a byte, from its buffer, to
the parallel bus.
LED 4, CENTR I/P flashes whenever the Centronics
Parallel port of the PSI BOX receives a byte from the printer
port of a computer, the byte is stored in the PSI BOX internal
buffer.
Since the Centronics port is either an input OR an output
only one of these LEDs will be in use for the particular PSI
BOX configuration chosen.
Figure 4-1. The Centronics Leds. ____________________________ _
○○○○ ○

Selecting The Direction Of The Centronics Port.

_________________________________________ _
DIP switch 6 on switch block 1 is used to determine
whether the Centronics Parallel port is an input or an output.
Page 32
Talk
Listen
Xmit
Recvr
Centr O/P
Centr I/P
Power On
Parallel Port
Chapter 4